Номер 3, страница 87, часть 1 - гдз по физике 9 класс рабочая тетрадь Грачев, Погожев

Авторы: Грачев А. В., Погожев В. А., Боков П. Ю., Вишнякова Е. А.

Тип: рабочая тетрадь

Издательство: Просвещение

Год издания: 2021 - 2026

Часть: 1

Цвет обложки: синий

ISBN: 978-5-09-098826-1 (ч.1) 978-5-09-098880-3 (ч.2) 978-5-09-098881-0 (ч.3)

Часть 1. Глава 2. Динамика. Параграф 18. Силы всемирного тяготения. Закон всемирного тяготения - номер 3, страница 87.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
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                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Просвещение"
                            "field_cases" => null
                            "field_translit" => "prosveschenie"
                          ]
                          #original: array:6 [
                            "id" => 5153
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Просвещение"
                            "field_cases" => null
                            "field_translit" => "prosveschenie"
                          ]
                          #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 {#1133
                      #items: array:4 [
                        0 => App\Models\Term {#1134
                          #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" => 4180
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Грачев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Александр"
                            "field_patronymic" => "Васильевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4180
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Грачев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Александр"
                            "field_patronymic" => "Васильевич"
                            "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 {#1135
                          #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" => 5484
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Погожев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Владимир"
                            "field_patronymic" => "Александрович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 5484
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Погожев"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Владимир"
                            "field_patronymic" => "Александрович"
                            "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 => "*"
                          ]
                        }
                        2 => App\Models\Term {#1136
                          #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" => 3888
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Боков"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Павел"
                            "field_patronymic" => "Юрьевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 3888
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Боков"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Павел"
                            "field_patronymic" => "Юрьевич"
                            "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 => "*"
                          ]
                        }
                        3 => App\Models\Term {#1137
                          #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" => 4007
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Вишнякова"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Екатерина"
                            "field_patronymic" => "Анатольевна"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4007
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Вишнякова"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Екатерина"
                            "field_patronymic" => "Анатольевна"
                            "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 {#1138
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1139
                      #items: array:1 [
                        0 => App\Models\Term {#1140
                          #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" => 6736
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "рабочая тетрадь"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => "рабочие тетради"
                            "field_short_name" => "рт"
                            "field_short_name_foreign" => null
                            "field_translit" => "rabochaya tetrad"
                          ]
                          #original: array:10 [
                            "id" => 6736
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "рабочая тетрадь"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [ …6]
                            "field_plural_form" => "рабочие тетради"
                            "field_short_name" => "рт"
                            "field_short_name_foreign" => null
                            "field_translit" => "rabochaya tetrad"
                          ]
                          #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 {#1141
                      #items: array:1 [
                        0 => App\Models\Term {#1142
                          #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 {#1143
                      #items: array:1 [
                        0 => App\Models\Term {#1144
                          #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 {#1145
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1146
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1147
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1148
                      #items: array:1 [
                        0 => App\Models\Term {#1149
                          #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 [ …6]
                            "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 [ …6]
                            "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" => "6"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1150
                      #items: array:1 [
                        0 => App\Models\Term {#1151
                          #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" => 33
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "стереотипное"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "stereotipnoe"
                          ]
                          #original: array:6 [
                            "id" => 33
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "стереотипное"
                            "field_cases" => array:6 [ …6]
                            "field_translit" => "stereotipnoe"
                          ]
                          #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 {#1152
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2021"
                    "field_publication_year_until" => null
                    "field_part" => "1, 2, 3"
                    "field_part_writing" => "Часть"
                    "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" => "594"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/grachev-rt/"
                    "field_isbn" => "978-5-09-098826-1 (ч.1) 978-5-09-098880-3 (ч.2) 978-5-09-098881-0 (ч.3)"
                    "field_cover" => array:3 [
                      0 => "/media/fizika_09/grachev-rt/covers/cover1.webp?ts=1759003248"
                      1 => "/media/fizika_09/grachev-rt/covers/cover2.webp?ts=1759003248"
                      2 => "/media/fizika_09/grachev-rt/covers/cover3.webp?ts=1759003248"
                    ]
                    "field_cover_alts" => array:3 [
                      0 => ""
                      1 => ""
                      2 => ""
                    ]
                    "field_covers" => array:3 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover1.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2293"
                        "height" => "2989"
                      ]
                      1 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover2.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2265"
                        "height" => "3003"
                      ]
                      2 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover3.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2241"
                        "height" => "2999"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1153
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1154
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1155
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/9-klass/fizika/grachev-rabochaya-tetrad"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1156
                      #items: array:1 [
                        0 => App\Models\Term {#1157
                          #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" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #original: array:50 [
                    "id" => 1203
                    "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 {#1128}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1129}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1131}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1133}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1138}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1139}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1141}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1143}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1145}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1146}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1147}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1148}
                    "field_publication_number" => "6"
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1150}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1152}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2021"
                    "field_publication_year_until" => null
                    "field_part" => "1, 2, 3"
                    "field_part_writing" => "Часть"
                    "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" => "594"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/grachev-rt/"
                    "field_isbn" => "978-5-09-098826-1 (ч.1) 978-5-09-098880-3 (ч.2) 978-5-09-098881-0 (ч.3)"
                    "field_cover" => array:3 [
                      0 => "/media/fizika_09/grachev-rt/covers/cover1.webp?ts=1759003248"
                      1 => "/media/fizika_09/grachev-rt/covers/cover2.webp?ts=1759003248"
                      2 => "/media/fizika_09/grachev-rt/covers/cover3.webp?ts=1759003248"
                    ]
                    "field_cover_alts" => array:3 [
                      0 => ""
                      1 => ""
                      2 => ""
                    ]
                    "field_covers" => array:3 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover1.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2293"
                        "height" => "2989"
                      ]
                      1 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover2.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2265"
                        "height" => "3003"
                      ]
                      2 => array:4 [
                        "path" => "/media/fizika_09/grachev-rt/covers/cover3.webp?ts=1759003248"
                        "alt" => ""
                        "width" => "2241"
                        "height" => "2999"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1153}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1154}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1155}
                    "field_url" => "/9-klass/fizika/grachev-rabochaya-tetrad"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1156}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #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 {#1158
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1434806
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => null
            "field_branch_order" => "1"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1127}
            "field_page_start" => "4"
            "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 {#1160}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1158}
          ]
          #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 {#1159
          #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" => 1434820
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Динамика"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1164
              #items: array:1 [
                0 => App\Models\Term {#1161
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => null
                  ]
                  #original: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => 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_page_start" => "53"
            "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 {#1163
              #items: array:1 [
                0 => App\Models\Book {#1126}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1162
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1434820
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Динамика"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1164}
            "field_page_start" => "53"
            "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 {#1163}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1162}
          ]
          #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 {#1165
          #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" => 1434827
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Силы всемирного тяготения. Закон всемирного тяготения"
            "field_branch_order" => "18"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1169
              #items: array:1 [
                0 => App\Models\Term {#1166
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #original: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [ …6]
                    "field_page_check_not_needed" => null
                    "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_page_start" => "87"
            "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 {#1168
              #items: array:1 [
                0 => App\Models\Book {#1126}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1177
              #items: array:1 [
                0 => App\Models\Branch {#1176
                  #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" => 1434820
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Динамика"
                    "field_branch_order" => "2"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1178 …2}
                    "field_page_start" => "53"
                    "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 {#1179 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1180 …2}
                  ]
                  #original: array:24 [
                    "id" => 1434820
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Динамика"
                    "field_branch_order" => "2"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1178 …2}
                    "field_page_start" => "53"
                    "field_branch_display" => "0"
                    "field_branch_expanded" => "0"
                    "field_display_branch_in_title" => "1"
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                    "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 {#1179 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1180 …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" => 1434827
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Силы всемирного тяготения. Закон всемирного тяготения"
            "field_branch_order" => "18"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1169}
            "field_page_start" => "87"
            "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 {#1168}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1177}
          ]
          #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 {#1074
      #items: array:2 [
        0 => App\Models\Element {#1105
          #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" => 1698399
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1097
              #items: array:1 [
                0 => App\Models\Edition {#1103
                  #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" => 6173
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1101 …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 {#1102 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1100 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1099 …2}
                    "field_content_source" => null
                  ]
                  #original: array:21 [
                    "id" => 6173
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1101 …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 {#1102 …2}
                    "field_comment" => null
                    "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1100 …2}
                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1099 …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" => "1435011"
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            "text" => "<p><strong>3.</strong> Один из возможных способов определения гравитационной постоянной состоит в следующем. Внутри закреплённого большого свинцового шара массой $\text{M}$ делают тонкий вертикальный канал, проходящий через центр шара. Затем на расстоянии $\text{R}$ от центра этого шара на оси канала вначале над шаром, а затем под ним подвешивают на нити шарик массой $\text{m}$. Получите формулу для вычисления гравитационной постоянной, зная разность $\Delta F$ показаний динамометра, к которому прикреплён верхний конец нити.</p><p><strong>Решение.</strong></p><p>Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину $\Delta F$.</p><p><em>Ответ:</em> ___________.</p>"
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            "text" => "<p><strong>3.</strong> Один из возможных способов определения гравитационной постоянной состоит в следующем. Внутри закреплённого большого свинцового шара массой $\text{M}$ делают тонкий вертикальный канал, проходящий через центр шара. Затем на расстоянии $\text{R}$ от центра этого шара на оси канала вначале над шаром, а затем под ним подвешивают на нити шарик массой $\text{m}$. Получите формулу для вычисления гравитационной постоянной, зная разность $\Delta F$ показаний динамометра, к которому прикреплён верхний конец нити.</p><p><strong>Решение.</strong></p><p>Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину $\Delta F$.</p><p><em>Ответ:</em> ___________.</p>"
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            "text" => "<p> <strong>Дано:</strong> </p> <p> Масса большого свинцового шара: $M$ <br> Масса маленького шарика: $m$ <br> Расстояние от центра большого шара до центра маленького шарика: $R$ <br> Разность показаний динамометра: $ΔF$ </p> <p> <strong>Найти:</strong> </p> <p> Формулу для вычисления гравитационной постоянной $G$. </p> <p> <strong>Решение:</strong> </p> <p> Рассмотрим два случая расположения маленького шарика. Динамометр измеряет силу натяжения нити $T$. Так как шарик находится в равновесии, сила натяжения нити уравновешивает все остальные силы, действующие на него по вертикали. </p> <p> 1. Маленький шарик находится <strong>над</strong> большим шаром на расстоянии $R$ от его центра. <br> На шарик действуют три силы, направленные вертикально: <br> - Сила тяжести $F_{тяж} = mg$, направленная вниз. <br> - Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, также направленная вниз (к центру большого шара). <br> - Сила натяжения нити $T_1$, направленная вверх. </p> <p> Показания динамометра в этом случае равны силе натяжения $F_1 = T_1$. Из условия равновесия: <br> $T_1 = mg + F_M$ <br> $F_1 = mg + G \frac{M m}{R^2}$ </p> <p> 2. Маленький шарик находится <strong>под</strong> большим шаром (внутри канала) на расстоянии $R$ от его центра. <br> На шарик действуют три силы: <br> - Сила тяжести $F_{тяж} = mg$, направленная вниз. <br> - Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, теперь направленная вверх (к центру большого шара). <br> - Сила натяжения нити $T_2$, направленная вверх. </p> <p> Показания динамометра в этом случае равны $F_2 = T_2$. Из условия равновесия: <br> $T_2 + F_M = mg$ <br> $T_2 = mg - F_M$ <br> $F_2 = mg - G \frac{M m}{R^2}$ </p> <p> Разность показаний динамометра $ΔF$ по условию равна: <br> $ΔF = F_1 - F_2 = \left( mg + G \frac{M m}{R^2} \right) - \left( mg - G \frac{M m}{R^2} \right)$ <br> $ΔF = mg + G \frac{M m}{R^2} - mg + G \frac{M m}{R^2}$ <br> $ΔF = 2 G \frac{M m}{R^2}$ </p> <p> Выразим из этой формулы гравитационную постоянную $G$: <br> $G = \frac{ΔF \cdot R^2}{2 M m}$ </p> <p> <strong>Ответ:</strong> $G = \frac{ΔF \cdot R^2}{2 M m}$ </p> <hr> <p> <strong>Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину ΔF.</strong> </p> <p> <strong>Дано:</strong> </p> <p> Для оценки выберем реалистичные параметры для лабораторной установки: <br> - Ускорение свободного падения: $g ≈ 9.8 \text{ м/с²}$ <br> - Гравитационная постоянная: $G ≈ 6.67 \times 10^{-11} \text{ Н} \cdot \text{м²}/\text{кг²}$ <br> - Плотность свинца: $ρ ≈ 11340 \text{ кг/м³}$ <br> - Радиус большого свинцового шара: $r_{шара} = 20 \text{ см}$ <br> - Расстояние от центра большого шара до маленького: $R = 25 \text{ см}$ (немного больше радиуса) </p> <p> Перевод в систему СИ: <br> $r_{шара} = 0.2 \text{ м}$ <br> $R = 0.25 \text{ м}$ </p> <p> <strong>Найти:</strong> </p> <p> Отношение $\frac{F_{тяж}}{ΔF}$. </p> <p> <strong>Решение:</strong> </p> <p> Нам нужно найти отношение $\frac{F_{тяж}}{ΔF}$, где $F_{тяж} = mg$. Из первой части задачи мы знаем, что $ΔF = 2 G \frac{M m}{R^2}$. </p> <p> Подставим выражение для $ΔF$ в искомое отношение: <br> $\frac{F_{тяж}}{ΔF} = \frac{mg}{2 G \frac{M m}{R^2}}$ </p> <p> Масса маленького шарика $m$ сокращается: <br> $\frac{F_{тяж}}{ΔF} = \frac{g R^2}{2 G M}$ </p> <p> Теперь вычислим массу большого свинцового шара $M$. <br> $M = ρ \cdot V = ρ \cdot \frac{4}{3} \pi r_{шара}^3$ <br> $M ≈ 11340 \cdot \frac{4}{3} \cdot 3.14 \cdot (0.2)^3 ≈ 11340 \cdot 4.187 \cdot 0.008 ≈ 380 \text{ кг}$ </p> <p> Подставим все значения в формулу для отношения: <br> $\frac{F_{тяж}}{ΔF} ≈ \frac{9.8 \cdot (0.25)^2}{2 \cdot 6.67 \times 10^{-11} \cdot 380} = \frac{9.8 \cdot 0.0625}{50692 \times 10^{-11}} = \frac{0.6125}{5.07 \times 10^{-7}}$ <br> $\frac{F_{тяж}}{ΔF} ≈ 0.12 \times 10^7 = 1.2 \times 10^6$ </p> <p> Таким образом, сила тяжести, действующая на маленький шарик, примерно в 1.2 миллиона раз превышает разность показаний динамометра. Это показывает, насколько слабой является гравитационная сила между телами лабораторных размеров по сравнению с силой притяжения к Земле, и почему измерение $ΔF$ требует очень высокой точности. </p> <p> <strong>Ответ:</strong> Сила тяжести превышает величину $ΔF$ примерно в $1.2 \times 10^6$ раз. </p>"
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            "text" => "<p> <strong>Дано:</strong> </p> <p> Масса большого свинцового шара: $M$ <br> Масса маленького шарика: $m$ <br> Расстояние от центра большого шара до центра маленького шарика: $R$ <br> Разность показаний динамометра: $ΔF$ </p> <p> <strong>Найти:</strong> </p> <p> Формулу для вычисления гравитационной постоянной $G$. </p> <p> <strong>Решение:</strong> </p> <p> Рассмотрим два случая расположения маленького шарика. Динамометр измеряет силу натяжения нити $T$. Так как шарик находится в равновесии, сила натяжения нити уравновешивает все остальные силы, действующие на него по вертикали. </p> <p> 1. Маленький шарик находится <strong>над</strong> большим шаром на расстоянии $R$ от его центра. <br> На шарик действуют три силы, направленные вертикально: <br> - Сила тяжести $F_{тяж} = mg$, направленная вниз. <br> - Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, также направленная вниз (к центру большого шара). <br> - Сила натяжения нити $T_1$, направленная вверх. </p> <p> Показания динамометра в этом случае равны силе натяжения $F_1 = T_1$. Из условия равновесия: <br> $T_1 = mg + F_M$ <br> $F_1 = mg + G \frac{M m}{R^2}$ </p> <p> 2. Маленький шарик находится <strong>под</strong> большим шаром (внутри канала) на расстоянии $R$ от его центра. <br> На шарик действуют три силы: <br> - Сила тяжести $F_{тяж} = mg$, направленная вниз. <br> - Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, теперь направленная вверх (к центру большого шара). <br> - Сила натяжения нити $T_2$, направленная вверх. </p> <p> Показания динамометра в этом случае равны $F_2 = T_2$. Из условия равновесия: <br> $T_2 + F_M = mg$ <br> $T_2 = mg - F_M$ <br> $F_2 = mg - G \frac{M m}{R^2}$ </p> <p> Разность показаний динамометра $ΔF$ по условию равна: <br> $ΔF = F_1 - F_2 = \left( mg + G \frac{M m}{R^2} \right) - \left( mg - G \frac{M m}{R^2} \right)$ <br> $ΔF = mg + G \frac{M m}{R^2} - mg + G \frac{M m}{R^2}$ <br> $ΔF = 2 G \frac{M m}{R^2}$ </p> <p> Выразим из этой формулы гравитационную постоянную $G$: <br> $G = \frac{ΔF \cdot R^2}{2 M m}$ </p> <p> <strong>Ответ:</strong> $G = \frac{ΔF \cdot R^2}{2 M m}$ </p> <hr> <p> <strong>Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину ΔF.</strong> </p> <p> <strong>Дано:</strong> </p> <p> Для оценки выберем реалистичные параметры для лабораторной установки: <br> - Ускорение свободного падения: $g ≈ 9.8 \text{ м/с²}$ <br> - Гравитационная постоянная: $G ≈ 6.67 \times 10^{-11} \text{ Н} \cdot \text{м²}/\text{кг²}$ <br> - Плотность свинца: $ρ ≈ 11340 \text{ кг/м³}$ <br> - Радиус большого свинцового шара: $r_{шара} = 20 \text{ см}$ <br> - Расстояние от центра большого шара до маленького: $R = 25 \text{ см}$ (немного больше радиуса) </p> <p> Перевод в систему СИ: <br> $r_{шара} = 0.2 \text{ м}$ <br> $R = 0.25 \text{ м}$ </p> <p> <strong>Найти:</strong> </p> <p> Отношение $\frac{F_{тяж}}{ΔF}$. </p> <p> <strong>Решение:</strong> </p> <p> Нам нужно найти отношение $\frac{F_{тяж}}{ΔF}$, где $F_{тяж} = mg$. Из первой части задачи мы знаем, что $ΔF = 2 G \frac{M m}{R^2}$. </p> <p> Подставим выражение для $ΔF$ в искомое отношение: <br> $\frac{F_{тяж}}{ΔF} = \frac{mg}{2 G \frac{M m}{R^2}}$ </p> <p> Масса маленького шарика $m$ сокращается: <br> $\frac{F_{тяж}}{ΔF} = \frac{g R^2}{2 G M}$ </p> <p> Теперь вычислим массу большого свинцового шара $M$. <br> $M = ρ \cdot V = ρ \cdot \frac{4}{3} \pi r_{шара}^3$ <br> $M ≈ 11340 \cdot \frac{4}{3} \cdot 3.14 \cdot (0.2)^3 ≈ 11340 \cdot 4.187 \cdot 0.008 ≈ 380 \text{ кг}$ </p> <p> Подставим все значения в формулу для отношения: <br> $\frac{F_{тяж}}{ΔF} ≈ \frac{9.8 \cdot (0.25)^2}{2 \cdot 6.67 \times 10^{-11} \cdot 380} = \frac{9.8 \cdot 0.0625}{50692 \times 10^{-11}} = \frac{0.6125}{5.07 \times 10^{-7}}$ <br> $\frac{F_{тяж}}{ΔF} ≈ 0.12 \times 10^7 = 1.2 \times 10^6$ </p> <p> Таким образом, сила тяжести, действующая на маленький шарик, примерно в 1.2 миллиона раз превышает разность показаний динамометра. Это показывает, насколько слабой является гравитационная сила между телами лабораторных размеров по сравнению с силой притяжения к Земле, и почему измерение $ΔF$ требует очень высокой точности. </p> <p> <strong>Ответ:</strong> Сила тяжести превышает величину $ΔF$ примерно в $1.2 \times 10^6$ раз. </p>"
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№3 (с. 87)
Условие. №3 (с. 87)
скриншот условия
Физика, 9 класс рабочая тетрадь, авторы: Грачев Александр Васильевич, Погожев Владимир Александрович, Боков Павел Юрьевич, Вишнякова Екатерина Анатольевна, издательство Просвещение, Москва, 2021, Часть 1, страница 87, номер 3, Условие
Физика, 9 класс рабочая тетрадь, авторы: Грачев Александр Васильевич, Погожев Владимир Александрович, Боков Павел Юрьевич, Вишнякова Екатерина Анатольевна, издательство Просвещение, Москва, 2021, Часть 1, страница 87, номер 3, Условие (продолжение 2)

3. Один из возможных способов определения гравитационной постоянной состоит в следующем. Внутри закреплённого большого свинцового шара массой $\text{M}$ делают тонкий вертикальный канал, проходящий через центр шара. Затем на расстоянии $\text{R}$ от центра этого шара на оси канала вначале над шаром, а затем под ним подвешивают на нити шарик массой $\text{m}$. Получите формулу для вычисления гравитационной постоянной, зная разность $\Delta F$ показаний динамометра, к которому прикреплён верхний конец нити.

Решение.

Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину $\Delta F$.

Ответ: ___________.

Решение. №3 (с. 87)

Дано:

Масса большого свинцового шара: $M$
Масса маленького шарика: $m$
Расстояние от центра большого шара до центра маленького шарика: $R$
Разность показаний динамометра: $ΔF$

Найти:

Формулу для вычисления гравитационной постоянной $G$.

Решение:

Рассмотрим два случая расположения маленького шарика. Динамометр измеряет силу натяжения нити $T$. Так как шарик находится в равновесии, сила натяжения нити уравновешивает все остальные силы, действующие на него по вертикали.

1. Маленький шарик находится над большим шаром на расстоянии $R$ от его центра.
На шарик действуют три силы, направленные вертикально:
- Сила тяжести $F_{тяж} = mg$, направленная вниз.
- Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, также направленная вниз (к центру большого шара).
- Сила натяжения нити $T_1$, направленная вверх.

Показания динамометра в этом случае равны силе натяжения $F_1 = T_1$. Из условия равновесия:
$T_1 = mg + F_M$
$F_1 = mg + G \frac{M m}{R^2}$

2. Маленький шарик находится под большим шаром (внутри канала) на расстоянии $R$ от его центра.
На шарик действуют три силы:
- Сила тяжести $F_{тяж} = mg$, направленная вниз.
- Гравитационная сила притяжения со стороны большого шара $F_M = G \frac{M m}{R^2}$, теперь направленная вверх (к центру большого шара).
- Сила натяжения нити $T_2$, направленная вверх.

Показания динамометра в этом случае равны $F_2 = T_2$. Из условия равновесия:
$T_2 + F_M = mg$
$T_2 = mg - F_M$
$F_2 = mg - G \frac{M m}{R^2}$

Разность показаний динамометра $ΔF$ по условию равна:
$ΔF = F_1 - F_2 = \left( mg + G \frac{M m}{R^2} \right) - \left( mg - G \frac{M m}{R^2} \right)$
$ΔF = mg + G \frac{M m}{R^2} - mg + G \frac{M m}{R^2}$
$ΔF = 2 G \frac{M m}{R^2}$

Выразим из этой формулы гравитационную постоянную $G$:
$G = \frac{ΔF \cdot R^2}{2 M m}$

Ответ: $G = \frac{ΔF \cdot R^2}{2 M m}$


Оцените, во сколько раз сила тяжести, действующая на маленький шарик, превышает величину ΔF.

Дано:

Для оценки выберем реалистичные параметры для лабораторной установки:
- Ускорение свободного падения: $g ≈ 9.8 \text{ м/с²}$
- Гравитационная постоянная: $G ≈ 6.67 \times 10^{-11} \text{ Н} \cdot \text{м²}/\text{кг²}$
- Плотность свинца: $ρ ≈ 11340 \text{ кг/м³}$
- Радиус большого свинцового шара: $r_{шара} = 20 \text{ см}$
- Расстояние от центра большого шара до маленького: $R = 25 \text{ см}$ (немного больше радиуса)

Перевод в систему СИ:
$r_{шара} = 0.2 \text{ м}$
$R = 0.25 \text{ м}$

Найти:

Отношение $\frac{F_{тяж}}{ΔF}$.

Решение:

Нам нужно найти отношение $\frac{F_{тяж}}{ΔF}$, где $F_{тяж} = mg$. Из первой части задачи мы знаем, что $ΔF = 2 G \frac{M m}{R^2}$.

Подставим выражение для $ΔF$ в искомое отношение:
$\frac{F_{тяж}}{ΔF} = \frac{mg}{2 G \frac{M m}{R^2}}$

Масса маленького шарика $m$ сокращается:
$\frac{F_{тяж}}{ΔF} = \frac{g R^2}{2 G M}$

Теперь вычислим массу большого свинцового шара $M$.
$M = ρ \cdot V = ρ \cdot \frac{4}{3} \pi r_{шара}^3$
$M ≈ 11340 \cdot \frac{4}{3} \cdot 3.14 \cdot (0.2)^3 ≈ 11340 \cdot 4.187 \cdot 0.008 ≈ 380 \text{ кг}$

Подставим все значения в формулу для отношения:
$\frac{F_{тяж}}{ΔF} ≈ \frac{9.8 \cdot (0.25)^2}{2 \cdot 6.67 \times 10^{-11} \cdot 380} = \frac{9.8 \cdot 0.0625}{50692 \times 10^{-11}} = \frac{0.6125}{5.07 \times 10^{-7}}$
$\frac{F_{тяж}}{ΔF} ≈ 0.12 \times 10^7 = 1.2 \times 10^6$

Таким образом, сила тяжести, действующая на маленький шарик, примерно в 1.2 миллиона раз превышает разность показаний динамометра. Это показывает, насколько слабой является гравитационная сила между телами лабораторных размеров по сравнению с силой притяжения к Земле, и почему измерение $ΔF$ требует очень высокой точности.

Ответ: Сила тяжести превышает величину $ΔF$ примерно в $1.2 \times 10^6$ раз.

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