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Номер 8.9, страница 44 - гдз по физике 8-11 класс учебник, задачник Гельфгат, Генденштейн
Авторы: Гельфгат И. М., Генденштейн Л. Э., Кирик Л. А.
Тип: Учебник, задачник
Издательство: Илекса
Год издания: 2005 - 2026
Цвет обложки: синий мужчина в красном, летит на черном шаре
ISBN: 978-5-89237-332-6
Популярные ГДЗ в 8 классе
Задачи. Механика. 8. Комбинированные задачи по механике - номер 8.9, страница 44.
App\Models\Task {#1030 // resources/views/models/task/default.blade.php #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288195 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-9" "field_display_title" => "8.9" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037 #items: array:1 [ 0 => App\Models\Term {#1036 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 26 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "номер" "field_cases" => array:6 [ "field_accusative_case" => "номер" "field_creative_case" => "номером" "field_dative_case" => "номеру" "field_genitive_case" => "номера" "field_nominative_case" => "номер" "field_prepositional_case" => "номере" ] "field_short_name" => "№" ] #original: array:6 [ "id" => 26 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "номер" "field_cases" => array:6 [ "field_accusative_case" => "номер" "field_creative_case" => "номером" "field_dative_case" => "номеру" "field_genitive_case" => "номера" "field_nominative_case" => "номер" "field_prepositional_case" => "номере" ] "field_short_name" => "№" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035 #items: [] #escapeWhenCastingToString: false } "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1076 #items: array:1 [ 0 => App\Models\Branch {#1034 #connection: "mysql" #table: "branches" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1287866 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Задачи" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1039 #items: [] #escapeWhenCastingToString: false } "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1038 #items: array:1 [ 0 => App\Models\Book {#1040 #connection: "mysql" #table: "books" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:50 [ "id" => 5401 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_tree_default_status" => "tasks" "field_pages_status" => null "field_subject" => Illuminate\Database\Eloquent\Collection {#1041 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1043 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1048 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1050 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1054 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1055 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1057 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1059 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1061 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1062 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1063 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1064 …2} "field_publication_number" => "6" "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1065 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1067 …2} "field_under_the_edition_degree" => null "field_cover_description" => "мужчина в красном, летит на черном шаре" "field_publication_year" => "2005" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебное издание" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1001" "field_priority" => null "field_default_folder" => "/fizika_08/gelfgat-u/" "field_isbn" => "978-5-89237-332-6" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1068 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1069 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1070 …2} "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1071 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #original: array:50 [ "id" => 5401 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_tree_default_status" => "tasks" "field_pages_status" => null "field_subject" => Illuminate\Database\Eloquent\Collection {#1041 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1043 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1048 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1050 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1054 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1055 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1057 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1059 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1061 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1062 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1063 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1064 …2} "field_publication_number" => "6" "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1065 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1067 …2} "field_under_the_edition_degree" => null "field_cover_description" => "мужчина в красном, летит на черном шаре" "field_publication_year" => "2005" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебное издание" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1001" "field_priority" => null "field_default_folder" => "/fizika_08/gelfgat-u/" "field_isbn" => "978-5-89237-332-6" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1068 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1069 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1070 …2} "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1071 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1073 #items: [] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1287866 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Задачи" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1039} "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1038} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1073} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "parent_branches" => Illuminate\Database\Eloquent\Collection {#1154 #items: array:3 [ 0 => App\Models\Branch {#1164 #connection: "mysql" #table: "branches" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1287866 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Задачи" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1165 #items: [] #escapeWhenCastingToString: false } "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1201 #items: array:1 [ 0 => App\Models\Book {#1166 #connection: "mysql" #table: "books" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:50 [ "id" => 5401 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_tree_default_status" => "tasks" "field_pages_status" => null "field_subject" => Illuminate\Database\Eloquent\Collection {#1168 #items: array:1 [ 0 => App\Models\Term {#1167 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:10 [ "id" => 6493 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Физика" "field_abbreviated_name" => null "field_cases" => array:6 [ …6] "field_foreign_lang_name" => null "field_short_name" => null "field_subject_type" => "technical_subject" "field_translit" => "fizika" ] #original: array:10 [ "id" => 6493 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Физика" "field_abbreviated_name" => null "field_cases" => array:6 [ …6] "field_foreign_lang_name" => null "field_short_name" => null "field_subject_type" => "technical_subject" "field_translit" => "fizika" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_class" => Illuminate\Database\Eloquent\Collection {#1169 #items: array:4 [ 0 => App\Models\Term {#1170 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 5457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "8" "field_cases" => array:6 [ …6] "field_translit" => "vosmoj" ] #original: array:6 [ "id" => 5457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "8" "field_cases" => array:6 [ …6] "field_translit" => "vosmoj" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 1 => App\Models\Term {#1171 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 5458 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "9" "field_cases" => array:6 [ …6] "field_translit" => "devjatyj" ] #original: array:6 [ "id" => 5458 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "9" "field_cases" => array:6 [ …6] "field_translit" => "devjatyj" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 2 => App\Models\Term {#1172 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 5459 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "10" "field_cases" => array:6 [ …6] "field_translit" => "desjatyj" ] #original: array:6 [ "id" => 5459 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "10" "field_cases" => array:6 [ …6] "field_translit" => "desjatyj" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 3 => App\Models\Term {#1173 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 5460 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "11" "field_cases" => array:6 [ …6] "field_translit" => "odinadcatyj" ] #original: array:6 [ "id" => 5460 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "11" "field_cases" => array:6 [ …6] "field_translit" => "odinadcatyj" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_publisher" => Illuminate\Database\Eloquent\Collection {#1174 #items: array:1 [ 0 => App\Models\Term {#1175 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 5158 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Илекса" "field_cases" => null "field_translit" => "ileksa" ] #original: array:6 [ "id" => 5158 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Илекса" "field_cases" => null "field_translit" => "ileksa" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_author" => Illuminate\Database\Eloquent\Collection {#1176 #items: array:3 [ 0 => App\Models\Term {#1177 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:12 [ "id" => 4102 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Гельфгат" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Илья" "field_patronymic" => "Маркович" "field_surname_rp" => null ] #original: array:12 [ "id" => 4102 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Гельфгат" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Илья" "field_patronymic" => "Маркович" "field_surname_rp" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 1 => App\Models\Term {#1178 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:12 [ "id" => 4104 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Генденштейн" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Лев" "field_patronymic" => "Элевич" "field_surname_rp" => "Генденштейна" ] #original: array:12 [ "id" => 4104 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Генденштейн" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Лев" "field_patronymic" => "Элевич" "field_surname_rp" => "Генденштейна" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 2 => App\Models\Term {#1179 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:12 [ "id" => 4583 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Кирик" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Леонид" "field_patronymic" => "Анатольевич" "field_surname_rp" => null ] #original: array:12 [ "id" => 4583 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Кирик" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Леонид" "field_patronymic" => "Анатольевич" "field_surname_rp" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1180 #items: [] #escapeWhenCastingToString: false } "field_book_type" => Illuminate\Database\Eloquent\Collection {#1181 #items: array:1 [ 0 => App\Models\Term {#1182 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:10 [ "id" => 6673 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Учебник, задачник" "field_book_type_foreign" => null "field_cases" => array:6 [ …6] "field_plural_form" => null "field_short_name" => null "field_short_name_foreign" => null "field_translit" => "uchebnik, zadachnik" ] #original: array:10 [ "id" => 6673 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Учебник, задачник" "field_book_type_foreign" => null "field_cases" => array:6 [ …6] "field_plural_form" => null "field_short_name" => null "field_short_name_foreign" => null "field_translit" => "uchebnik, zadachnik" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_country" => Illuminate\Database\Eloquent\Collection {#1183 #items: array:1 [ 0 => App\Models\Term {#1184 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 9 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Россия" "field_cases" => array:6 [ …6] "field_translit" => "rossiya" ] #original: array:6 [ "id" => 9 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Россия" "field_cases" => array:6 [ …6] "field_translit" => "rossiya" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_city" => Illuminate\Database\Eloquent\Collection {#1185 #items: array:1 [ 0 => App\Models\Term {#1186 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 15 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Москва" "field_cases" => array:6 [ …6] "field_translit" => "moskva" ] #original: array:6 [ "id" => 15 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Москва" "field_cases" => array:6 [ …6] "field_translit" => "moskva" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_series" => Illuminate\Database\Eloquent\Collection {#1187 #items: [] #escapeWhenCastingToString: false } "field_umk" => Illuminate\Database\Eloquent\Collection {#1188 #items: [] #escapeWhenCastingToString: false } "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1189 #items: [] #escapeWhenCastingToString: false } "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1190 #items: [] #escapeWhenCastingToString: false } "field_publication_number" => "6" "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1191 #items: array:1 [ 0 => App\Models\Term {#1192 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 35 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "исправленное" "field_cases" => array:6 [ …6] "field_translit" => "ispravlennoe" ] #original: array:6 [ "id" => 35 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "исправленное" "field_cases" => array:6 [ …6] "field_translit" => "ispravlennoe" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1193 #items: [] #escapeWhenCastingToString: false } "field_under_the_edition_degree" => null "field_cover_description" => "мужчина в красном, летит на черном шаре" "field_publication_year" => "2005" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебное издание" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1001" "field_priority" => null "field_default_folder" => "/fizika_08/gelfgat-u/" "field_isbn" => "978-5-89237-332-6" "field_cover" => array:1 [ 0 => "/media/fizika_08/gelfgat-u/covers/cover1.webp?ts=1755898771" ] "field_cover_alts" => array:1 [ 0 => "" ] "field_covers" => array:1 [ 0 => array:4 [ "path" => "/media/fizika_08/gelfgat-u/covers/cover1.webp?ts=1755898771" "alt" => "" "width" => "1813" "height" => "2441" ] ] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1194 #items: [] #escapeWhenCastingToString: false } "field_new_book" => Illuminate\Database\Eloquent\Collection {#1195 #items: [] #escapeWhenCastingToString: false } "field_old_book" => Illuminate\Database\Eloquent\Collection {#1196 #items: [] #escapeWhenCastingToString: false } "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1197 #items: array:1 [ 0 => App\Models\Term {#1198 #connection: "mysql" #table: "terms" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 49 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "синий" "field_cases" => array:6 [ …6] "field_translit" => "siniy" ] #original: array:6 [ "id" => 49 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "синий" "field_cases" => array:6 [ …6] "field_translit" => "siniy" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ "class" => 379 "subject" => 556 "class_subject" => 492 ] ] #original: array:50 [ "id" => 5401 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_tree_default_status" => "tasks" "field_pages_status" => null "field_subject" => Illuminate\Database\Eloquent\Collection {#1168} "field_class" => Illuminate\Database\Eloquent\Collection {#1169} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1174} "field_author" => Illuminate\Database\Eloquent\Collection {#1176} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1180} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1181} "field_country" => Illuminate\Database\Eloquent\Collection {#1183} "field_city" => Illuminate\Database\Eloquent\Collection {#1185} "field_series" => Illuminate\Database\Eloquent\Collection {#1187} "field_umk" => Illuminate\Database\Eloquent\Collection {#1188} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1189} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1190} "field_publication_number" => "6" "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1191} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1193} "field_under_the_edition_degree" => null "field_cover_description" => "мужчина в красном, летит на черном шаре" "field_publication_year" => "2005" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебное издание" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1001" "field_priority" => null "field_default_folder" => "/fizika_08/gelfgat-u/" "field_isbn" => "978-5-89237-332-6" "field_cover" => array:1 [ 0 => "/media/fizika_08/gelfgat-u/covers/cover1.webp?ts=1755898771" ] "field_cover_alts" => array:1 [ 0 => "" ] "field_covers" => array:1 [ 0 => array:4 [ "path" => "/media/fizika_08/gelfgat-u/covers/cover1.webp?ts=1755898771" "alt" => "" "width" => "1813" "height" => "2441" ] ] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1194} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1195} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1196} "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1197} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ "class" => 379 "subject" => 556 "class_subject" => 492 ] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1199 #items: [] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1287866 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Задачи" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1165} "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1201} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1199} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 1 => App\Models\Branch {#1200 #connection: "mysql" #table: "branches" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1287867 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Механика" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1202 #items: [] #escapeWhenCastingToString: false } "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1203 #items: array:1 [ 0 => App\Models\Book {#1166} ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1204 #items: array:1 [ 0 => App\Models\Branch {#1034} ] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1287867 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Механика" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1202} "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1203} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1204} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 2 => App\Models\Branch {#1205 #connection: "mysql" #table: "branches" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1287875 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "8. Комбинированные задачи по механике" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1206 #items: [] #escapeWhenCastingToString: false } "field_page_start" => "43" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1207 #items: array:1 [ 0 => App\Models\Book {#1166} ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1251 #items: array:1 [ 0 => App\Models\Branch {#1208 #connection: "mysql" #table: "branches" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1287867 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Механика" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1210 …2} "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1209 …2} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1244 …2} ] #original: array:24 [ "id" => 1287867 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Механика" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1210 …2} "field_page_start" => "5" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1209 …2} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1244 …2} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1287875 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "8. Комбинированные задачи по механике" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1206} "field_page_start" => "43" "field_branch_display" => "0" "field_branch_expanded" => "0" "field_display_branch_in_title" => "1" "field_display_task_interval" => "0" "field_display_branch_page" => "1" "field_branch_title_in_content" => "0" "field_navigation_title" => null "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_branch_cover" => [] "field_branch_covers" => [] "book" => Illuminate\Database\Eloquent\Collection {#1207} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1251} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1148 #items: array:3 [ 0 => App\Models\Element {#1143 #connection: "mysql" #table: "elements" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:7 [ "id" => 1477993 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1135 #items: array:1 [ 0 => App\Models\Edition {#1142 #connection: "mysql" #table: "editions" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:21 [ "id" => 5410 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1141 …2} "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "stas" "field_edition_type" => "statement" "field_root_dir" => "0-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1139 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1138 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1137 …2} "field_content_source" => null ] #original: array:21 [ "id" => 5410 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1141 …2} "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "stas" "field_edition_type" => "statement" "field_root_dir" => "0-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1139 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1138 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1137 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "text" => "<p><strong>8.9*.</strong> Каковы ускорения грузов показанной на рисунке системы? Участки нити, не соприкасающиеся с блоками, вертикальны.</p><p>К задаче 8.9</p>" "img" => array:2 [ 0 => array:5 [ "name" => "9-1.jpg" "alt" => null "width" => "1445" "height" => 243 "path" => "/media/fizika_08/gelfgat-u/0-08/9-1.webp?ts=1756049783" ] 1 => array:5 [ "name" => "9-2.jpg" "alt" => null "width" => "447" "height" => 519 "path" => "/media/fizika_08/gelfgat-u/0-08/9-2.webp?ts=1756049783" ] ] ] #original: array:7 [ "id" => 1477993 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1135} "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "text" => "<p><strong>8.9*.</strong> Каковы ускорения грузов показанной на рисунке системы? Участки нити, не соприкасающиеся с блоками, вертикальны.</p><p>К задаче 8.9</p>" "img" => array:2 [ 0 => array:5 [ "name" => "9-1.jpg" "alt" => null "width" => "1445" "height" => 243 "path" => "/media/fizika_08/gelfgat-u/0-08/9-1.webp?ts=1756049783" ] 1 => array:5 [ "name" => "9-2.jpg" "alt" => null "width" => "447" "height" => 519 "path" => "/media/fizika_08/gelfgat-u/0-08/9-2.webp?ts=1756049783" ] ] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 1 => App\Models\Element {#1136 #connection: "mysql" #table: "elements" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 1478524 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1127 #items: array:1 [ 0 => App\Models\Edition {#1134 #connection: "mysql" #table: "editions" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:21 [ "id" => 5411 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1133 …2} "field_content_type" => "free" "field_content_mode" => "image" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "stas" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1130 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1131 …2} "field_process_formula" => "" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1129 …2} "field_content_source" => null ] #original: array:21 [ "id" => 5411 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1133 …2} "field_content_type" => "free" "field_content_mode" => "image" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "stas" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1130 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1131 …2} "field_process_formula" => "" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1129 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "img" => array:1 [ 0 => array:5 [ "name" => "9-1.jpg" "alt" => null "width" => "1446" "height" => 450 "path" => "/media/fizika_08/gelfgat-u/1-08/9-1.webp?ts=1756049847" ] ] ] #original: array:6 [ "id" => 1478524 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1127} "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "img" => array:1 [ 0 => array:5 [ "name" => "9-1.jpg" "alt" => null "width" => "1446" "height" => 450 "path" => "/media/fizika_08/gelfgat-u/1-08/9-1.webp?ts=1756049847" ] ] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 2 => App\Models\Element {#1125 #connection: "mysql" #table: "elements" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 1737888 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1119 #items: array:1 [ 0 => App\Models\Edition {#1128 #connection: "mysql" #table: "editions" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:21 [ "id" => 6336 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение 2" "field_order" => "3" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1123 …2} "field_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "2-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1124 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1118 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1122 …2} "field_content_source" => null ] #original: array:21 [ "id" => 6336 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение 2" "field_order" => "3" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1123 …2} "field_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "2-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1124 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1118 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1122 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "text" => "<p><strong>Дано:</strong></p><p>Массы грузов: $m_1$, $m_2$, $m_3$</p><p>Ускорение свободного падения: $\text{g}$</p><p><strong>Найти:</strong></p><p>Ускорения грузов: $a_1$, $a_2$, $a_3$</p><p><strong>Решение:</strong></p><p>Введём систему координат с осью OY, направленной вертикально вниз. Пусть $y_1, y_2, y_3$ – координаты грузов $m_1, m_2, m_3$ соответственно. В системе используется одна нерастяжимая и невесомая нить, поэтому её общая длина $\text{L}$ постоянна. Выразим длину нити через координаты грузов, учитывая, что груз $m_2$ подвешен к подвижному блоку, а грузы $m_1$ и $m_3$ – к концам нити, перекинутой через два неподвижных и один подвижный блок.</p><p>Длина нити (без учёта постоянных участков на блоках) выражается как: $L = y_1 + 2y_2 + y_3$.</p><p>Поскольку длина нити не меняется со временем ($L = const$), её вторая производная по времени равна нулю. Продифференцировав это уравнение дважды по времени, получим кинематическую связь между ускорениями грузов (проекциями ускорений на ось OY):</p><p>$\frac{d^2L}{dt^2} = \frac{d^2y_1}{dt^2} + 2\frac{d^2y_2}{dt^2} + \frac{d^2y_3}{dt^2} = 0$</p><p>$a_1 + 2a_2 + a_3 = 0$ (1)</p><p>Теперь запишем уравнения движения для каждого груза, используя второй закон Ньютона. Пусть $\text{T}$ – сила натяжения нити. Так как нить невесома и трение в блоках отсутствует, сила натяжения одинакова по всей длине нити.</p><p>Для груза $m_1$:</p><p>$m_1 a_1 = m_1 g - T$ (2)</p><p>Для груза $m_2$ (вместе с невесомым подвижным блоком): на него действует сила тяжести $m_2g$ и две силы натяжения нити $\text{2T}$, направленные вверх.</p><p>$m_2 a_2 = m_2 g - 2T$ (3)</p><p>Для груза $m_3$:</p><p>$m_3 a_3 = m_3 g - T$ (4)</p><p>Мы получили систему из четырех уравнений (1), (2), (3), (4) для четырех неизвестных: $a_1, a_2, a_3$ и $\text{T}$.</p><p>Из уравнений (2), (3) и (4) выразим ускорения через силу натяжения $\text{T}$:</p><p>$a_1 = g - \frac{T}{m_1}$</p><p>$a_2 = g - \frac{2T}{m_2}$</p><p>$a_3 = g - \frac{T}{m_3}$</p><p>Подставим эти выражения в уравнение кинематической связи (1):</p><p>$(g - \frac{T}{m_1}) + 2(g - \frac{2T}{m_2}) + (g - \frac{T}{m_3}) = 0$</p><p>$4g - T(\frac{1}{m_1} + \frac{4}{m_2} + \frac{1}{m_3}) = 0$</p><p>Отсюда найдем силу натяжения нити $\text{T}$:</p><p>$T(\frac{m_2 m_3 + 4m_1 m_3 + m_1 m_2}{m_1 m_2 m_3}) = 4g$</p><p>$T = \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Теперь подставим найденное значение $\text{T}$ в выражения для ускорений.</p><p>Ускорение груза $m_1$:</p><p>$a_1 = g - \frac{T}{m_1} = g - \frac{1}{m_1} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_1 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Ускорение груза $m_2$:</p><p>$a_2 = g - \frac{2T}{m_2} = g - \frac{2}{m_2} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{8 m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_2 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 8m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Ускорение груза $m_3$:</p><p>$a_3 = g - \frac{T}{m_3} = g - \frac{1}{m_3} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_3 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Полученные выражения представляют собой проекции ускорений на ось, направленную вниз. Знак результата определяет направление движения: положительное значение означает движение вниз, отрицательное — вверх.</p><p><strong>Ответ:</strong></p><p>Ускорения грузов (в проекции на вертикальную ось, направленную вниз) равны:</p><p>$a_1 = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>$a_2 = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>$a_3 = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p>" ] #original: array:6 [ "id" => 1737888 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1119} "task" => array:2 [ "refs" => "1288195" "type" => "task" ] "text" => "<p><strong>Дано:</strong></p><p>Массы грузов: $m_1$, $m_2$, $m_3$</p><p>Ускорение свободного падения: $\text{g}$</p><p><strong>Найти:</strong></p><p>Ускорения грузов: $a_1$, $a_2$, $a_3$</p><p><strong>Решение:</strong></p><p>Введём систему координат с осью OY, направленной вертикально вниз. Пусть $y_1, y_2, y_3$ – координаты грузов $m_1, m_2, m_3$ соответственно. В системе используется одна нерастяжимая и невесомая нить, поэтому её общая длина $\text{L}$ постоянна. Выразим длину нити через координаты грузов, учитывая, что груз $m_2$ подвешен к подвижному блоку, а грузы $m_1$ и $m_3$ – к концам нити, перекинутой через два неподвижных и один подвижный блок.</p><p>Длина нити (без учёта постоянных участков на блоках) выражается как: $L = y_1 + 2y_2 + y_3$.</p><p>Поскольку длина нити не меняется со временем ($L = const$), её вторая производная по времени равна нулю. Продифференцировав это уравнение дважды по времени, получим кинематическую связь между ускорениями грузов (проекциями ускорений на ось OY):</p><p>$\frac{d^2L}{dt^2} = \frac{d^2y_1}{dt^2} + 2\frac{d^2y_2}{dt^2} + \frac{d^2y_3}{dt^2} = 0$</p><p>$a_1 + 2a_2 + a_3 = 0$ (1)</p><p>Теперь запишем уравнения движения для каждого груза, используя второй закон Ньютона. Пусть $\text{T}$ – сила натяжения нити. Так как нить невесома и трение в блоках отсутствует, сила натяжения одинакова по всей длине нити.</p><p>Для груза $m_1$:</p><p>$m_1 a_1 = m_1 g - T$ (2)</p><p>Для груза $m_2$ (вместе с невесомым подвижным блоком): на него действует сила тяжести $m_2g$ и две силы натяжения нити $\text{2T}$, направленные вверх.</p><p>$m_2 a_2 = m_2 g - 2T$ (3)</p><p>Для груза $m_3$:</p><p>$m_3 a_3 = m_3 g - T$ (4)</p><p>Мы получили систему из четырех уравнений (1), (2), (3), (4) для четырех неизвестных: $a_1, a_2, a_3$ и $\text{T}$.</p><p>Из уравнений (2), (3) и (4) выразим ускорения через силу натяжения $\text{T}$:</p><p>$a_1 = g - \frac{T}{m_1}$</p><p>$a_2 = g - \frac{2T}{m_2}$</p><p>$a_3 = g - \frac{T}{m_3}$</p><p>Подставим эти выражения в уравнение кинематической связи (1):</p><p>$(g - \frac{T}{m_1}) + 2(g - \frac{2T}{m_2}) + (g - \frac{T}{m_3}) = 0$</p><p>$4g - T(\frac{1}{m_1} + \frac{4}{m_2} + \frac{1}{m_3}) = 0$</p><p>Отсюда найдем силу натяжения нити $\text{T}$:</p><p>$T(\frac{m_2 m_3 + 4m_1 m_3 + m_1 m_2}{m_1 m_2 m_3}) = 4g$</p><p>$T = \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Теперь подставим найденное значение $\text{T}$ в выражения для ускорений.</p><p>Ускорение груза $m_1$:</p><p>$a_1 = g - \frac{T}{m_1} = g - \frac{1}{m_1} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_1 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Ускорение груза $m_2$:</p><p>$a_2 = g - \frac{2T}{m_2} = g - \frac{2}{m_2} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{8 m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_2 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 8m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Ускорение груза $m_3$:</p><p>$a_3 = g - \frac{T}{m_3} = g - \frac{1}{m_3} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$</p><p>$a_3 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>Полученные выражения представляют собой проекции ускорений на ось, направленную вниз. Знак результата определяет направление движения: положительное значение означает движение вниз, отрицательное — вверх.</p><p><strong>Ответ:</strong></p><p>Ускорения грузов (в проекции на вертикальную ось, направленную вниз) равны:</p><p>$a_1 = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>$a_2 = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p><p>$a_3 = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$</p>" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1288196" "type" => "task" ] "previous" => array:2 [ "refs" => "1288194" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1147 #items: array:1 [ 0 => App\Models\Book {#1166} ] #escapeWhenCastingToString: false } "page" => Illuminate\Database\Eloquent\Collection {#1115 #items: array:1 [ 0 => App\Models\BookPage {#1149 #connection: "mysql" #table: "book_pages" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:21 [ "id" => 1340395 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/page-44" "field_display_title" => "44" "field_folder" => "1" "field_image_name" => "44" "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1152 #items: [] #escapeWhenCastingToString: false } "field_weight" => "0" "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1121 #items: array:1 [ 0 => App\Models\Book {#1166} ] #escapeWhenCastingToString: false } "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "edition_groups" => Illuminate\Database\Eloquent\Collection {#1120 #items: [] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1109 #items: array:1 [ 0 => App\Models\Element {#1078 #connection: "mysql" #table: "elements" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ "id" => 1518516 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1110 …2} "book_page" => array:2 [ …2] "img" => array:1 [ …1] ] #original: array:6 [ "id" => 1518516 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1110 …2} "book_page" => array:2 [ …2] "img" => array:1 [ …1] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1340396" "type" => "book_page" ] "previous" => array:2 [ "refs" => "1340394" "type" => "book_page" ] "tasks" => Illuminate\Database\Eloquent\Collection {#1361 #items: array:6 [ 0 => App\Models\Task {#1373 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288195 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-9" "field_display_title" => "8.9" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1374 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1375 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1376 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1377 …2} "content" => Illuminate\Database\Eloquent\Collection {#1378 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1379 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1288195 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-9" "field_display_title" => "8.9" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1374 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1375 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1376 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1377 …2} "content" => Illuminate\Database\Eloquent\Collection {#1378 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1379 …2} "page" => array:2 [ …2] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 1 => App\Models\Task {#1380 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288196 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-10" "field_display_title" => "8.10" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1381 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1382 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1383 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1384 …2} "content" => Illuminate\Database\Eloquent\Collection {#1387 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1393 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1288196 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-10" "field_display_title" => "8.10" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1381 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1382 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1383 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1384 …2} "content" => Illuminate\Database\Eloquent\Collection {#1387 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1393 …2} "page" => array:2 [ …2] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 2 => App\Models\Task {#1386 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288197 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-11" "field_display_title" => "8.11" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1385 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1392 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1394 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1390 …2} "content" => Illuminate\Database\Eloquent\Collection {#1389 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1407 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1288197 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => 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false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 3 => App\Models\Task {#1391 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288198 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-12" "field_display_title" => "8.12" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1388 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1406 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1408 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1404 …2} "content" => Illuminate\Database\Eloquent\Collection {#1403 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1421 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1288198 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-12" "field_display_title" => "8.12" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1388 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1406 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1408 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1404 …2} "content" => Illuminate\Database\Eloquent\Collection {#1403 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1421 …2} "page" => array:2 [ …2] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } 4 => App\Models\Task {#1405 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ "id" => 1288199 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-13" "field_display_title" => "8.13" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1402 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1420 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1422 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1418 …2} "content" => Illuminate\Database\Eloquent\Collection {#1417 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1435 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1288199 "created_at" => "2026-04-10 13:58:26" …22 ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } 5 => App\Models\Task {#1419 #connection: "mysql" #table: "tasks" #primaryKey: "id" #keyType: "int" +incrementing: true #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:24 [ …24] #original: array:24 [ …24] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } ] #original: array:21 [ "id" => 1340395 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/page-44" "field_display_title" => "44" 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false } ] #original: array:24 [ "id" => 1288195 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "44" "field_page_end" => null "field_url" => "/8-klass/fizika/ileksa-gelfgat-uchebnik/08-9" "field_display_title" => "8.9" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "field_match" => null "breadcrumbs" => [] "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1076} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1154} "content" => Illuminate\Database\Eloquent\Collection {#1148} "next" => array:2 [ "refs" => "1288196" "type" => "task" ] "previous" => array:2 [ "refs" => "1288194" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1147} "page" => array:2 [ "refs" => "1340395" "type" => "book_page" ] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] }
№8.9 (с. 44)
Условие. №8.9 (с. 44)
скриншот условия
8.9*. Каковы ускорения грузов показанной на рисунке системы? Участки нити, не соприкасающиеся с блоками, вертикальны.
К задаче 8.9
Решение. №8.9 (с. 44)
Решение 2. №8.9 (с. 44)
Дано:
Массы грузов: $m_1$, $m_2$, $m_3$
Ускорение свободного падения: $\text{g}$
Найти:
Ускорения грузов: $a_1$, $a_2$, $a_3$
Решение:
Введём систему координат с осью OY, направленной вертикально вниз. Пусть $y_1, y_2, y_3$ – координаты грузов $m_1, m_2, m_3$ соответственно. В системе используется одна нерастяжимая и невесомая нить, поэтому её общая длина $\text{L}$ постоянна. Выразим длину нити через координаты грузов, учитывая, что груз $m_2$ подвешен к подвижному блоку, а грузы $m_1$ и $m_3$ – к концам нити, перекинутой через два неподвижных и один подвижный блок.
Длина нити (без учёта постоянных участков на блоках) выражается как: $L = y_1 + 2y_2 + y_3$.
Поскольку длина нити не меняется со временем ($L = const$), её вторая производная по времени равна нулю. Продифференцировав это уравнение дважды по времени, получим кинематическую связь между ускорениями грузов (проекциями ускорений на ось OY):
$\frac{d^2L}{dt^2} = \frac{d^2y_1}{dt^2} + 2\frac{d^2y_2}{dt^2} + \frac{d^2y_3}{dt^2} = 0$
$a_1 + 2a_2 + a_3 = 0$ (1)
Теперь запишем уравнения движения для каждого груза, используя второй закон Ньютона. Пусть $\text{T}$ – сила натяжения нити. Так как нить невесома и трение в блоках отсутствует, сила натяжения одинакова по всей длине нити.
Для груза $m_1$:
$m_1 a_1 = m_1 g - T$ (2)
Для груза $m_2$ (вместе с невесомым подвижным блоком): на него действует сила тяжести $m_2g$ и две силы натяжения нити $\text{2T}$, направленные вверх.
$m_2 a_2 = m_2 g - 2T$ (3)
Для груза $m_3$:
$m_3 a_3 = m_3 g - T$ (4)
Мы получили систему из четырех уравнений (1), (2), (3), (4) для четырех неизвестных: $a_1, a_2, a_3$ и $\text{T}$.
Из уравнений (2), (3) и (4) выразим ускорения через силу натяжения $\text{T}$:
$a_1 = g - \frac{T}{m_1}$
$a_2 = g - \frac{2T}{m_2}$
$a_3 = g - \frac{T}{m_3}$
Подставим эти выражения в уравнение кинематической связи (1):
$(g - \frac{T}{m_1}) + 2(g - \frac{2T}{m_2}) + (g - \frac{T}{m_3}) = 0$
$4g - T(\frac{1}{m_1} + \frac{4}{m_2} + \frac{1}{m_3}) = 0$
Отсюда найдем силу натяжения нити $\text{T}$:
$T(\frac{m_2 m_3 + 4m_1 m_3 + m_1 m_2}{m_1 m_2 m_3}) = 4g$
$T = \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
Теперь подставим найденное значение $\text{T}$ в выражения для ускорений.
Ускорение груза $m_1$:
$a_1 = g - \frac{T}{m_1} = g - \frac{1}{m_1} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$
$a_1 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
Ускорение груза $m_2$:
$a_2 = g - \frac{2T}{m_2} = g - \frac{2}{m_2} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{8 m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$
$a_2 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 8m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
Ускорение груза $m_3$:
$a_3 = g - \frac{T}{m_3} = g - \frac{1}{m_3} \frac{4g m_1 m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g (1 - \frac{4 m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3})$
$a_3 = g \frac{m_1 m_2 + m_2 m_3 + 4m_1 m_3 - 4m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3} = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
Полученные выражения представляют собой проекции ускорений на ось, направленную вниз. Знак результата определяет направление движения: положительное значение означает движение вниз, отрицательное — вверх.
Ответ:
Ускорения грузов (в проекции на вертикальную ось, направленную вниз) равны:
$a_1 = g \frac{m_1 m_2 + 4m_1 m_3 - 3m_2 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
$a_2 = g \frac{m_1 m_2 + m_2 m_3 - 4m_1 m_3}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
$a_3 = g \frac{m_2 m_3 + 4m_1 m_3 - 3m_1 m_2}{m_1 m_2 + m_2 m_3 + 4m_1 m_3}$
Другие задания:
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