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Номер 2, страница 249 - гдз по физике 8 класс учебник Изергин
Авторы: Изергин Э. Т.
Тип: Учебник
Издательство: Русское слово
Год издания: 2019 - 2026
Цвет обложки: синий
ISBN: 978-5-533-01067-2
Популярные ГДЗ в 8 классе
Домашние экспериментальные задания - номер 2, страница 249.
App\Models\Task {#1024 // 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" => 1492608 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => "250" "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-2" "field_display_title" => "2" "field_outside_task" => "0" "field_task_type" => Illuminate\Database\Eloquent\Collection {#331 #items: array:1 [ 0 => App\Models\Term {#1029 #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 {#1026 #items: [] #escapeWhenCastingToString: false } "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#342 #items: array:1 [ 0 => App\Models\Branch {#1023 #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" => 1492207 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Домашние экспериментальные задания" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#333 #items: [] #escapeWhenCastingToString: false } "field_page_start" => "249" "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 {#1033 #items: array:1 [ 0 => App\Models\Book {#1030 #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" => 4168 "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 {#1032 #items: array:1 [ 0 => App\Models\Term {#1034 #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 [ "field_accusative_case" => "физику" "field_creative_case" => "физикой" "field_dative_case" => "физике" "field_genitive_case" => "физики" "field_nominative_case" => "физика" "field_prepositional_case" => "физике" ] "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 [ "field_accusative_case" => "физику" "field_creative_case" => "физикой" "field_dative_case" => "физике" "field_genitive_case" => "физики" "field_nominative_case" => "физика" "field_prepositional_case" => "физике" ] "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 {#1035 #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" => 5457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "8" "field_cases" => array:6 [ "field_accusative_case" => "восьмой" "field_creative_case" => "восьмым" "field_dative_case" => "восьмому" "field_genitive_case" => "восьмого" "field_nominative_case" => "восьмой" "field_prepositional_case" => "восьмом" ] "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 [ "field_accusative_case" => "восьмой" "field_creative_case" => "восьмым" "field_dative_case" => "восьмому" "field_genitive_case" => "восьмого" "field_nominative_case" => "восьмой" "field_prepositional_case" => "восьмом" ] "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 => "*" ] } ] #escapeWhenCastingToString: false } "field_publisher" => Illuminate\Database\Eloquent\Collection {#1037 #items: array:1 [ 0 => App\Models\Term {#1038 #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" => 5176 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Русское слово" "field_cases" => null "field_translit" => "russkoe slovo" ] #original: array:6 [ "id" => 5176 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Русское слово" "field_cases" => null "field_translit" => "russkoe slovo" ] #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 {#1039 #items: array:1 [ 0 => App\Models\Term {#1040 #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" => 4491 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Изергин" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Эдуард" "field_patronymic" => "Тимофеевич" "field_surname_rp" => null ] #original: array:12 [ "id" => 4491 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Изергин" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Эдуард" "field_patronymic" => "Тимофеевич" "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 {#1041 #items: [] #escapeWhenCastingToString: false } "field_book_type" => Illuminate\Database\Eloquent\Collection {#1042 #items: array:1 [ 0 => App\Models\Term {#1043 #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" => 6671 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Учебник" "field_book_type_foreign" => null "field_cases" => array:6 [ "field_accusative_case" => "учебник" "field_creative_case" => "учебником" "field_dative_case" => "учебнику" "field_genitive_case" => "учебника" "field_nominative_case" => "учебник" "field_prepositional_case" => "учебнике" ] "field_plural_form" => null "field_short_name" => null "field_short_name_foreign" => null "field_translit" => "uchebnik" ] #original: array:10 [ "id" => 6671 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Учебник" "field_book_type_foreign" => null "field_cases" => array:6 [ "field_accusative_case" => "учебник" "field_creative_case" => "учебником" "field_dative_case" => "учебнику" "field_genitive_case" => "учебника" "field_nominative_case" => "учебник" "field_prepositional_case" => "учебнике" ] "field_plural_form" => null "field_short_name" => null "field_short_name_foreign" => null "field_translit" => "uchebnik" ] #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 {#1044 #items: array:1 [ 0 => App\Models\Term {#1045 #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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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 {#1046 #items: array:1 [ 0 => App\Models\Term {#1047 #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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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 {#1048 #items: [] #escapeWhenCastingToString: false } "field_umk" => Illuminate\Database\Eloquent\Collection {#1049 #items: [] #escapeWhenCastingToString: false } "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1050 #items: [] #escapeWhenCastingToString: false } "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1051 #items: array:1 [ 0 => App\Models\Term {#1052 #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" => 6706 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "ФГОС (старый)" "field_cases" => array:6 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "field_color" => null "field_end_year" => "2022" "field_start_year" => "2019" "field_translit" => "fgos-old" "field_type" => null ] #original: array:10 [ "id" => 6706 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "ФГОС (старый)" "field_cases" => array:6 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "field_color" => null "field_end_year" => "2022" "field_start_year" => "2019" "field_translit" => "fgos-old" "field_type" => 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_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1053 #items: [] #escapeWhenCastingToString: false } "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1054 #items: [] #escapeWhenCastingToString: false } "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для 8 класса общеобразовательных организаций" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "417" "field_priority" => null "field_default_folder" => "/fizika_08/izergin-u/" "field_isbn" => "978-5-533-01067-2" "field_cover" => array:1 [ 0 => "/media/fizika_08/izergin-u/covers/cover1.webp?ts=1760998278" ] "field_cover_alts" => array:1 [ 0 => "" ] "field_covers" => array:1 [ 0 => array:4 [ "path" => "/media/fizika_08/izergin-u/covers/cover1.webp?ts=1760998278" "alt" => "" "width" => "1608" "height" => "2576" ] ] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1055 #items: [] #escapeWhenCastingToString: false } "field_new_book" => Illuminate\Database\Eloquent\Collection {#1056 #items: [] #escapeWhenCastingToString: false } "field_old_book" => Illuminate\Database\Eloquent\Collection {#1057 #items: [] #escapeWhenCastingToString: false } "field_url" => "/8-klass/fizika/izergin-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1058 #items: array:1 [ 0 => App\Models\Term {#1059 #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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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 [ "field_accusative_case" => null "field_creative_case" => null "field_dative_case" => null "field_genitive_case" => null "field_nominative_case" => null "field_prepositional_case" => null ] "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" => 4168 "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 {#1032} "field_class" => Illuminate\Database\Eloquent\Collection {#1035} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1037} "field_author" => Illuminate\Database\Eloquent\Collection {#1039} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1041} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1042} "field_country" => Illuminate\Database\Eloquent\Collection {#1044} "field_city" => Illuminate\Database\Eloquent\Collection {#1046} "field_series" => Illuminate\Database\Eloquent\Collection {#1048} "field_umk" => Illuminate\Database\Eloquent\Collection {#1049} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1050} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1051} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1053} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1054} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для 8 класса общеобразовательных организаций" "field_allowed" => null "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "417" "field_priority" => null "field_default_folder" => "/fizika_08/izergin-u/" "field_isbn" => "978-5-533-01067-2" "field_cover" => array:1 [ 0 => "/media/fizika_08/izergin-u/covers/cover1.webp?ts=1760998278" ] "field_cover_alts" => array:1 [ 0 => "" ] "field_covers" => array:1 [ 0 => array:4 [ "path" => "/media/fizika_08/izergin-u/covers/cover1.webp?ts=1760998278" "alt" => "" "width" => "1608" "height" => "2576" ] ] "field_popular_book" => "0" "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1055} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1056} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1057} "field_url" => "/8-klass/fizika/izergin-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1058} "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 {#1060 #items: [] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1492207 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "Домашние экспериментальные задания" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#333} "field_page_start" => "249" "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 {#1033} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1060} ] #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 {#1061 #items: array:1 [ 0 => App\Models\Branch {#1023} ] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1062 #items: array:2 [ 0 => App\Models\Element {#1063 #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" => 1774750 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1064 #items: array:1 [ 0 => App\Models\Edition {#1065 #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" => 6496 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1066 #items: array:1 [ 0 => App\Models\Term {#1038} ] #escapeWhenCastingToString: false } "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => "0" "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 {#1067 #items: [] #escapeWhenCastingToString: false } "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1068 #items: [] #escapeWhenCastingToString: false } "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1069 #items: [] #escapeWhenCastingToString: false } "field_content_source" => null ] #original: array:21 [ "id" => 6496 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1066} "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => "0" "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 {#1067} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1068} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1069} "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" => "1492608" "type" => "task" ] "text" => "<p>Задание 2</p><p><strong>Измерение удельной теплоты плавления льда</strong></p><p><strong>Цель:</strong> научиться определять удельную теплоту плавления льда.</p><p><strong>Порядок выполнения</strong></p><p><strong>1.</strong> Возьмите кусочек льда (сосульки). Можно приготовить несколько кубиков льда в морозильной камере холодильника. Положите лёд в кружку и подождите, пока его температура не повысится до $0^{\circ}\text{C}$ (лёд начнёт таять). Заметьте время в минутах от начала таяния льда до полного его превращения в воду. После этого заметьте время, в течение которого вода, в которую превратился лёд, нагреется от $0^{\circ}\text{C}$ до $5^{\circ}\text{C}$.</p><p><strong>2.</strong> Будем считать, что лёд, а затем вода получали от окружающего воздуха в единицу времени одинаковое количество теплоты $\text{Q}$. Тогда:</p><p>На плавление льда пошло количество теплоты $Q \cdot t_1 = m \cdot \lambda$.</p><p>На нагревание воды пошло количество теплоты $Q \cdot t_2 = c m \Delta T$.</p><p>Разделим первое уравнение на второе. Получим: $\frac{t_1}{t_2} = \frac{\lambda}{c \Delta T}$.</p><p>Тогда $\lambda = \frac{t_1 c \Delta T}{t_2}$.</p><p>Рассчитайте удельную теплоту плавления льда, значение удельной теплоёмкости воды возьмите из таблицы в учебнике.</p><p><strong>3.</strong> Сделайте письменный отчёт о проделанной работе.</p>" "img" => array:2 [ 0 => array:5 [ "name" => "2-1.jpg" "alt" => null "width" => "1559" "height" => 541 "path" => "/media/fizika_08/izergin-u/0-dom/2-1.webp?ts=1761329271" ] 1 => array:5 [ "name" => "2-2.jpg" "alt" => null "width" => "1545" "height" => 1130 "path" => "/media/fizika_08/izergin-u/0-dom/2-2.webp?ts=1761329271" ] ] ] #original: array:7 [ "id" => 1774750 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1064} "task" => array:2 [ "refs" => "1492608" "type" => "task" ] "text" => "<p>Задание 2</p><p><strong>Измерение удельной теплоты плавления льда</strong></p><p><strong>Цель:</strong> научиться определять удельную теплоту плавления льда.</p><p><strong>Порядок выполнения</strong></p><p><strong>1.</strong> Возьмите кусочек льда (сосульки). Можно приготовить несколько кубиков льда в морозильной камере холодильника. Положите лёд в кружку и подождите, пока его температура не повысится до $0^{\circ}\text{C}$ (лёд начнёт таять). Заметьте время в минутах от начала таяния льда до полного его превращения в воду. После этого заметьте время, в течение которого вода, в которую превратился лёд, нагреется от $0^{\circ}\text{C}$ до $5^{\circ}\text{C}$.</p><p><strong>2.</strong> Будем считать, что лёд, а затем вода получали от окружающего воздуха в единицу времени одинаковое количество теплоты $\text{Q}$. Тогда:</p><p>На плавление льда пошло количество теплоты $Q \cdot t_1 = m \cdot \lambda$.</p><p>На нагревание воды пошло количество теплоты $Q \cdot t_2 = c m \Delta T$.</p><p>Разделим первое уравнение на второе. Получим: $\frac{t_1}{t_2} = \frac{\lambda}{c \Delta T}$.</p><p>Тогда $\lambda = \frac{t_1 c \Delta T}{t_2}$.</p><p>Рассчитайте удельную теплоту плавления льда, значение удельной теплоёмкости воды возьмите из таблицы в учебнике.</p><p><strong>3.</strong> Сделайте письменный отчёт о проделанной работе.</p>" "img" => array:2 [ 0 => array:5 [ "name" => "2-1.jpg" "alt" => null "width" => "1559" "height" => 541 "path" => "/media/fizika_08/izergin-u/0-dom/2-1.webp?ts=1761329271" ] 1 => array:5 [ "name" => "2-2.jpg" "alt" => null "width" => "1545" "height" => 1130 "path" => "/media/fizika_08/izergin-u/0-dom/2-2.webp?ts=1761329271" ] ] ] #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 {#1070 #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" => 1851922 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1071 #items: array:1 [ 0 => App\Models\Edition {#1072 #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" => 7014 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1073 #items: array:1 [ 0 => App\Models\Term {#1074 #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" => 7012 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Gemini 2.5 Pro" "field_cases" => array:6 [ …6] "field_translit" => "gemini 2.5 pro" ] #original: array:6 [ "id" => 7012 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Gemini 2.5 Pro" "field_cases" => array:6 [ …6] "field_translit" => "gemini 2.5 pro" ] #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_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1075 #items: [] #escapeWhenCastingToString: false } "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1076 #items: [] #escapeWhenCastingToString: false } "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1077 #items: [] #escapeWhenCastingToString: false } "field_content_source" => null ] #original: array:21 [ "id" => 7014 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1073} "field_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1075} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1076} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1077} "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" => "1492608" "type" => "task" ] "text" => "<p>Поскольку данное задание представляет собой описание лабораторной работы, для его решения необходимо смоделировать проведение эксперимента и выполнить расчеты на основе гипотетических, но реалистичных данных. Ниже представлен письменный отчет о проделанной работе в соответствии с пунктом 3 задания.</p><p><strong>Цель:</strong> научиться определять удельную теплоту плавления льда.</p><p><strong>Порядок выполнения (в виде отчета о проведенных действиях):</strong></p><p><strong>1.</strong> Кусочек льда был помещен в кружку и выдержан при комнатной температуре до момента, когда его температура достигла 0 °C и начался процесс таяния.</p><p><strong>2.</strong> С помощью секундомера было зафиксировано время $t_1$, необходимое для полного плавления льда. В ходе эксперимента это время составило 30 минут.</p><p><strong>3.</strong> После полного превращения льда в воду было зафиксировано время $t_2$, за которое температура воды поднялась с 0 °C до 5 °C. Это время составило 2 минуты.</p><p><strong>4.</strong> На основе полученных данных была рассчитана удельная теплота плавления льда.</p><p><strong>Результаты и вычисления:</strong></p><p><strong>Дано:</strong></p><p>Время плавления льда, $t_1 = 30 \text{ мин}$</p><p>Время нагревания воды, $t_2 = 2 \text{ мин}$</p><p>Начальная температура воды, $T_{нач} = 0^\circ C$</p><p>Конечная температура воды, $T_{кон} = 5^\circ C$</p><p>Удельная теплоемкость воды (табличное значение), $c = 4200 \frac{Дж}{кг \cdot ^\circ C}$</p><p>Перевод в систему СИ:</p><p>$t_1 = 30 \cdot 60 = 1800 \text{ c}$</p><p>$t_2 = 2 \cdot 60 = 120 \text{ c}$</p><p>Изменение температуры, $\Delta T = T_{кон} - T_{нач} = 5^\circ C - 0^\circ C = 5 \text{ K}$</p><p><strong>Найти:</strong></p><p>Удельная теплота плавления льда, $\lambda$.</p><p><strong>Решение:</strong></p><p>Основное допущение метода заключается в том, что теплообмен с окружающей средой происходит с постоянной мощностью $\text{P}$, то есть лед и вода получают одинаковое количество теплоты в единицу времени.</p><p>Количество теплоты, необходимое для плавления льда ($Q_1$) массой $\text{m}$, было получено за время $t_1$:</p><p>$Q_1 = \lambda m = P \cdot t_1$ (1)</p><p>Количество теплоты для нагревания образовавшейся воды ($Q_2$) на $\Delta T$ было получено за время $t_2$:</p><p>$Q_2 = c m \Delta T = P \cdot t_2$ (2)</p><p>Разделив почленно уравнение (1) на уравнение (2), получаем:</p><p>$\frac{\lambda m}{c m \Delta T} = \frac{P \cdot t_1}{P \cdot t_2}$</p><p>После сокращения одинаковых множителей ($\text{m}$ и $\text{P}$) получаем выражение для расчета удельной теплоты плавления $\lambda$:</p><p>$\frac{\lambda}{c \Delta T} = \frac{t_1}{t_2} \implies \lambda = \frac{t_1 \cdot c \cdot \Delta T}{t_2}$</p><p>Подставим экспериментальные и табличные данные в расчетную формулу:</p><p>$\lambda = \frac{1800 \text{ с} \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К}}{120 \text{ с}} = 15 \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К} = 315000 \frac{Дж}{кг} = 3.15 \cdot 10^5 \frac{Дж}{кг}$</p><p>Сравним полученное значение с табличным значением удельной теплоты плавления льда ($\lambda_{табл} \approx 3.3 \cdot 10^5 \frac{Дж}{кг}$).</p><p>Относительная погрешность эксперимента составляет:</p><p>$\epsilon = \left| \frac{\lambda_{табл} - \lambda}{\lambda_{табл}} \right| \cdot 100\% = \left| \frac{3.3 \cdot 10^5 - 3.15 \cdot 10^5}{3.3 \cdot 10^5} \right| \cdot 100\% \approx 4.5\%$</p><p>Полученная погрешность является небольшой, что говорит о приемлемой точности проведенного эксперимента. Основными источниками погрешности могли стать неточность измерения времени и непостоянство мощности теплопередачи от окружающего воздуха (по мере нагревания воды разность температур с воздухом уменьшается).</p><p><strong>Ответ:</strong> Удельная теплота плавления льда, определенная в ходе эксперимента, составила $\lambda = 3.15 \cdot 10^5 \frac{Дж}{кг}$.</p>" ] #original: array:6 [ "id" => 1851922 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1071} "task" => array:2 [ "refs" => "1492608" "type" => "task" ] "text" => "<p>Поскольку данное задание представляет собой описание лабораторной работы, для его решения необходимо смоделировать проведение эксперимента и выполнить расчеты на основе гипотетических, но реалистичных данных. Ниже представлен письменный отчет о проделанной работе в соответствии с пунктом 3 задания.</p><p><strong>Цель:</strong> научиться определять удельную теплоту плавления льда.</p><p><strong>Порядок выполнения (в виде отчета о проведенных действиях):</strong></p><p><strong>1.</strong> Кусочек льда был помещен в кружку и выдержан при комнатной температуре до момента, когда его температура достигла 0 °C и начался процесс таяния.</p><p><strong>2.</strong> С помощью секундомера было зафиксировано время $t_1$, необходимое для полного плавления льда. В ходе эксперимента это время составило 30 минут.</p><p><strong>3.</strong> После полного превращения льда в воду было зафиксировано время $t_2$, за которое температура воды поднялась с 0 °C до 5 °C. Это время составило 2 минуты.</p><p><strong>4.</strong> На основе полученных данных была рассчитана удельная теплота плавления льда.</p><p><strong>Результаты и вычисления:</strong></p><p><strong>Дано:</strong></p><p>Время плавления льда, $t_1 = 30 \text{ мин}$</p><p>Время нагревания воды, $t_2 = 2 \text{ мин}$</p><p>Начальная температура воды, $T_{нач} = 0^\circ C$</p><p>Конечная температура воды, $T_{кон} = 5^\circ C$</p><p>Удельная теплоемкость воды (табличное значение), $c = 4200 \frac{Дж}{кг \cdot ^\circ C}$</p><p>Перевод в систему СИ:</p><p>$t_1 = 30 \cdot 60 = 1800 \text{ c}$</p><p>$t_2 = 2 \cdot 60 = 120 \text{ c}$</p><p>Изменение температуры, $\Delta T = T_{кон} - T_{нач} = 5^\circ C - 0^\circ C = 5 \text{ K}$</p><p><strong>Найти:</strong></p><p>Удельная теплота плавления льда, $\lambda$.</p><p><strong>Решение:</strong></p><p>Основное допущение метода заключается в том, что теплообмен с окружающей средой происходит с постоянной мощностью $\text{P}$, то есть лед и вода получают одинаковое количество теплоты в единицу времени.</p><p>Количество теплоты, необходимое для плавления льда ($Q_1$) массой $\text{m}$, было получено за время $t_1$:</p><p>$Q_1 = \lambda m = P \cdot t_1$ (1)</p><p>Количество теплоты для нагревания образовавшейся воды ($Q_2$) на $\Delta T$ было получено за время $t_2$:</p><p>$Q_2 = c m \Delta T = P \cdot t_2$ (2)</p><p>Разделив почленно уравнение (1) на уравнение (2), получаем:</p><p>$\frac{\lambda m}{c m \Delta T} = \frac{P \cdot t_1}{P \cdot t_2}$</p><p>После сокращения одинаковых множителей ($\text{m}$ и $\text{P}$) получаем выражение для расчета удельной теплоты плавления $\lambda$:</p><p>$\frac{\lambda}{c \Delta T} = \frac{t_1}{t_2} \implies \lambda = \frac{t_1 \cdot c \cdot \Delta T}{t_2}$</p><p>Подставим экспериментальные и табличные данные в расчетную формулу:</p><p>$\lambda = \frac{1800 \text{ с} \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К}}{120 \text{ с}} = 15 \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К} = 315000 \frac{Дж}{кг} = 3.15 \cdot 10^5 \frac{Дж}{кг}$</p><p>Сравним полученное значение с табличным значением удельной теплоты плавления льда ($\lambda_{табл} \approx 3.3 \cdot 10^5 \frac{Дж}{кг}$).</p><p>Относительная погрешность эксперимента составляет:</p><p>$\epsilon = \left| \frac{\lambda_{табл} - \lambda}{\lambda_{табл}} \right| \cdot 100\% = \left| \frac{3.3 \cdot 10^5 - 3.15 \cdot 10^5}{3.3 \cdot 10^5} \right| \cdot 100\% \approx 4.5\%$</p><p>Полученная погрешность является небольшой, что говорит о приемлемой точности проведенного эксперимента. Основными источниками погрешности могли стать неточность измерения времени и непостоянство мощности теплопередачи от окружающего воздуха (по мере нагревания воды разность температур с воздухом уменьшается).</p><p><strong>Ответ:</strong> Удельная теплота плавления льда, определенная в ходе эксперимента, составила $\lambda = 3.15 \cdot 10^5 \frac{Дж}{кг}$.</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" => "1492609" "type" => "task" ] "previous" => array:2 [ "refs" => "1492607" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1078 #items: array:1 [ 0 => App\Models\Book {#1030} ] #escapeWhenCastingToString: false } "page" => Illuminate\Database\Eloquent\Collection {#1238 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"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 {#1090 #items: array:1 [ 0 => App\Models\Term {#1091 #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 => "*" ] } ] #escapeWhenCastingToString: false } "field_publisher" => Illuminate\Database\Eloquent\Collection {#1092 #items: array:1 [ 0 => App\Models\Term {#1093 #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" => 5176 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Русское слово" "field_cases" => null "field_translit" => "russkoe slovo" ] #original: array:6 [ "id" => 5176 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Русское слово" "field_cases" => null "field_translit" => "russkoe slovo" ] #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 {#1094 #items: array:1 [ 0 => App\Models\Term {#1095 #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" => 4491 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Изергин" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Эдуард" "field_patronymic" => "Тимофеевич" "field_surname_rp" => null ] #original: array:12 [ "id" => 4491 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "name" => "Изергин" "field_bio" => null "field_degree_rp" => null "field_foreign_lang_name" => null "field_foreign_lang_patronymic" => null "field_foreign_lang_surname" => null "field_name" => "Эдуард" "field_patronymic" => "Тимофеевич" "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 {#1096 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+preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:6 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "field_city" => Illuminate\Database\Eloquent\Collection {#1101 #items: array:1 [ 0 => App\Models\Term {#1102 #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 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] 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Illuminate\Database\Eloquent\Collection {#1112} "field_url" => "/8-klass/fizika/izergin-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1113} "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 } "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 {#1115 #items: [] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1116 #items: array:1 [ 0 => App\Models\Element {#1117 #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" => 1775042 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1118 #items: array:1 [ 0 => App\Models\Edition {#1119 #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 [ …21] #original: array:21 [ …21] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "book_page" => array:2 [ "refs" => "1492141" "type" => "book_page" ] "img" => array:1 [ 0 => array:5 [ "name" => "249-1.jpg" "alt" => null "width" => "1901" "height" => 2557 "path" => "/media/fizika_08/izergin-u/0-1/249-1.webp?ts=1761329767" ] ] ] #original: array:6 [ "id" => 1775042 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1118} "book_page" => array:2 [ "refs" => "1492141" "type" => "book_page" ] "img" => array:1 [ 0 => array:5 [ "name" => "249-1.jpg" "alt" => null "width" => "1901" "height" => 2557 "path" => "/media/fizika_08/izergin-u/0-1/249-1.webp?ts=1761329767" ] ] ] #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" => "1492142" "type" => "book_page" ] "previous" => array:2 [ "refs" => "1492140" "type" => "book_page" ] "tasks" => Illuminate\Database\Eloquent\Collection {#1125 #items: array:2 [ 0 => App\Models\Task {#1126 #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" => 1492607 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => null "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-1" "field_display_title" => "1" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1127 #items: array:1 [ 0 => App\Models\Term {#1128 #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 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #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 {#1129 #items: [] #escapeWhenCastingToString: false } "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1130 #items: array:1 [ 0 => App\Models\Branch {#1131 #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 [ …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 } "parent_branches" => Illuminate\Database\Eloquent\Collection {#1163 #items: array:1 [ 0 => App\Models\Branch {#1131} ] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1164 #items: array:2 [ 0 => App\Models\Element {#1165 #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 [ …7] #original: array:7 [ …7] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } 1 => App\Models\Element {#1172 #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 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1492608" "type" => "task" ] "previous" => array:2 [ "refs" => "1492606" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1180 #items: array:1 [ 0 => App\Models\Book {#1134 #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 [ …50] #original: array:50 [ …50] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "page" => array:2 [ "refs" => "1492141" "type" => "book_page" ] ] #original: array:24 [ "id" => 1492607 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => null "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-1" "field_display_title" => "1" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1127} "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 {#1129} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1130} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1163} "content" => Illuminate\Database\Eloquent\Collection {#1164} "next" => array:2 [ "refs" => "1492608" "type" => "task" ] "previous" => array:2 [ "refs" => "1492606" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1180} "page" => array:2 [ "refs" => "1492141" "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 => "*" ] } 1 => App\Models\Task {#1181 #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" => 1492608 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => "250" "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-2" "field_display_title" => "2" "field_outside_task" => "0" "field_task_type" => Illuminate\Database\Eloquent\Collection {#1182 #items: array:1 [ 0 => App\Models\Term {#1183 #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 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #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 {#1184 #items: [] #escapeWhenCastingToString: false } "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1185 #items: array:1 [ 0 => App\Models\Branch {#1186 #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 [ …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 } "parent_branches" => Illuminate\Database\Eloquent\Collection {#1218 #items: array:1 [ 0 => App\Models\Branch {#1186} ] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1219 #items: array:2 [ 0 => App\Models\Element {#1220 #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 [ …7] #original: array:7 [ …7] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } 1 => App\Models\Element {#1227 #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 [ …6] #original: array:6 [ …6] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1492609" "type" => "task" ] "previous" => array:2 [ "refs" => "1492607" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1235 #items: array:1 [ 0 => App\Models\Book {#1189 #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 [ …50] #original: array:50 [ …50] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ …1] } ] #escapeWhenCastingToString: false } "page" => array:2 [ "refs" => "1492141" "type" => "book_page" ] ] #original: array:24 [ "id" => 1492608 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => "250" "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-2" "field_display_title" => "2" "field_outside_task" => "0" "field_task_type" => Illuminate\Database\Eloquent\Collection {#1182} "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 {#1184} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1185} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1218} "content" => Illuminate\Database\Eloquent\Collection {#1219} "next" => array:2 [ "refs" => "1492609" "type" => "task" ] "previous" => array:2 [ "refs" => "1492607" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1235} "page" => array:2 [ "refs" => "1492141" "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 => "*" ] } ] #escapeWhenCastingToString: false } ] #original: array:21 [ "id" => 1492141 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_url" => "/8-klass/fizika/izergin-uchebnik/page-249" "field_display_title" => "249" "field_folder" => "1" "field_image_name" => "249" "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1086} "field_weight" => "0" "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1085} "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 {#1115} "content" => Illuminate\Database\Eloquent\Collection {#1116} "next" => array:2 [ "refs" => "1492142" "type" => "book_page" ] "previous" => array:2 [ "refs" => "1492140" "type" => "book_page" ] "tasks" => Illuminate\Database\Eloquent\Collection {#1125} ] #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" => 1492608 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "249" "field_page_end" => "250" "field_url" => "/8-klass/fizika/izergin-uchebnik/dom-2" "field_display_title" => "2" "field_outside_task" => "0" "field_task_type" => Illuminate\Database\Eloquent\Collection {#331} "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 {#1026} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#342} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1061} "content" => Illuminate\Database\Eloquent\Collection {#1062} "next" => array:2 [ "refs" => "1492609" "type" => "task" ] "previous" => array:2 [ "refs" => "1492607" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1078} "page" => array:2 [ "refs" => "1492141" "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 => "*" ] }
№2 (с. 249)
Условие. №2 (с. 249)
скриншот условия
Задание 2
Измерение удельной теплоты плавления льда
Цель: научиться определять удельную теплоту плавления льда.
Порядок выполнения
1. Возьмите кусочек льда (сосульки). Можно приготовить несколько кубиков льда в морозильной камере холодильника. Положите лёд в кружку и подождите, пока его температура не повысится до $0^{\circ}\text{C}$ (лёд начнёт таять). Заметьте время в минутах от начала таяния льда до полного его превращения в воду. После этого заметьте время, в течение которого вода, в которую превратился лёд, нагреется от $0^{\circ}\text{C}$ до $5^{\circ}\text{C}$.
2. Будем считать, что лёд, а затем вода получали от окружающего воздуха в единицу времени одинаковое количество теплоты $\text{Q}$. Тогда:
На плавление льда пошло количество теплоты $Q \cdot t_1 = m \cdot \lambda$.
На нагревание воды пошло количество теплоты $Q \cdot t_2 = c m \Delta T$.
Разделим первое уравнение на второе. Получим: $\frac{t_1}{t_2} = \frac{\lambda}{c \Delta T}$.
Тогда $\lambda = \frac{t_1 c \Delta T}{t_2}$.
Рассчитайте удельную теплоту плавления льда, значение удельной теплоёмкости воды возьмите из таблицы в учебнике.
3. Сделайте письменный отчёт о проделанной работе.
Решение. №2 (с. 249)
Поскольку данное задание представляет собой описание лабораторной работы, для его решения необходимо смоделировать проведение эксперимента и выполнить расчеты на основе гипотетических, но реалистичных данных. Ниже представлен письменный отчет о проделанной работе в соответствии с пунктом 3 задания.
Цель: научиться определять удельную теплоту плавления льда.
Порядок выполнения (в виде отчета о проведенных действиях):
1. Кусочек льда был помещен в кружку и выдержан при комнатной температуре до момента, когда его температура достигла 0 °C и начался процесс таяния.
2. С помощью секундомера было зафиксировано время $t_1$, необходимое для полного плавления льда. В ходе эксперимента это время составило 30 минут.
3. После полного превращения льда в воду было зафиксировано время $t_2$, за которое температура воды поднялась с 0 °C до 5 °C. Это время составило 2 минуты.
4. На основе полученных данных была рассчитана удельная теплота плавления льда.
Результаты и вычисления:
Дано:
Время плавления льда, $t_1 = 30 \text{ мин}$
Время нагревания воды, $t_2 = 2 \text{ мин}$
Начальная температура воды, $T_{нач} = 0^\circ C$
Конечная температура воды, $T_{кон} = 5^\circ C$
Удельная теплоемкость воды (табличное значение), $c = 4200 \frac{Дж}{кг \cdot ^\circ C}$
Перевод в систему СИ:
$t_1 = 30 \cdot 60 = 1800 \text{ c}$
$t_2 = 2 \cdot 60 = 120 \text{ c}$
Изменение температуры, $\Delta T = T_{кон} - T_{нач} = 5^\circ C - 0^\circ C = 5 \text{ K}$
Найти:
Удельная теплота плавления льда, $\lambda$.
Решение:
Основное допущение метода заключается в том, что теплообмен с окружающей средой происходит с постоянной мощностью $\text{P}$, то есть лед и вода получают одинаковое количество теплоты в единицу времени.
Количество теплоты, необходимое для плавления льда ($Q_1$) массой $\text{m}$, было получено за время $t_1$:
$Q_1 = \lambda m = P \cdot t_1$ (1)
Количество теплоты для нагревания образовавшейся воды ($Q_2$) на $\Delta T$ было получено за время $t_2$:
$Q_2 = c m \Delta T = P \cdot t_2$ (2)
Разделив почленно уравнение (1) на уравнение (2), получаем:
$\frac{\lambda m}{c m \Delta T} = \frac{P \cdot t_1}{P \cdot t_2}$
После сокращения одинаковых множителей ($\text{m}$ и $\text{P}$) получаем выражение для расчета удельной теплоты плавления $\lambda$:
$\frac{\lambda}{c \Delta T} = \frac{t_1}{t_2} \implies \lambda = \frac{t_1 \cdot c \cdot \Delta T}{t_2}$
Подставим экспериментальные и табличные данные в расчетную формулу:
$\lambda = \frac{1800 \text{ с} \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К}}{120 \text{ с}} = 15 \cdot 4200 \frac{Дж}{кг \cdot К} \cdot 5 \text{ К} = 315000 \frac{Дж}{кг} = 3.15 \cdot 10^5 \frac{Дж}{кг}$
Сравним полученное значение с табличным значением удельной теплоты плавления льда ($\lambda_{табл} \approx 3.3 \cdot 10^5 \frac{Дж}{кг}$).
Относительная погрешность эксперимента составляет:
$\epsilon = \left| \frac{\lambda_{табл} - \lambda}{\lambda_{табл}} \right| \cdot 100\% = \left| \frac{3.3 \cdot 10^5 - 3.15 \cdot 10^5}{3.3 \cdot 10^5} \right| \cdot 100\% \approx 4.5\%$
Полученная погрешность является небольшой, что говорит о приемлемой точности проведенного эксперимента. Основными источниками погрешности могли стать неточность измерения времени и непостоянство мощности теплопередачи от окружающего воздуха (по мере нагревания воды разность температур с воздухом уменьшается).
Ответ: Удельная теплота плавления льда, определенная в ходе эксперимента, составила $\lambda = 3.15 \cdot 10^5 \frac{Дж}{кг}$.
Другие задания:
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