Номер 12.7, страница 90 - гдз по физике 10-11 класс задачник Гельфгат, Генденштейн

Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета

Авторы: Гельфгат И. М., Генденштейн Л. Э., Кирик Л. А.

Тип: Задачник

Издательство: Илекса

Год издания: 2008 - 2026

Уровень обучения: профильный

Цвет обложки: красный лупа, парень едет на велосипеде

ISBN: 978-5-89237-252-7

Механика. Механические колебания и волны. 12. Механические колебания. Упражнения - номер 12.7, страница 90.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
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                            "name" => "11"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "одиннадцатый"
                              "field_creative_case" => "одиннадцатым"
                              "field_dative_case" => "одиннадцатому"
                              "field_genitive_case" => "одинадцатого"
                              "field_nominative_case" => "одинадцатый"
                              "field_prepositional_case" => "одиннадцатом"
                            ]
                            "field_translit" => "odinadcatyj"
                          ]
                          #original: array:6 [
                            "id" => 5460
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "11"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "одиннадцатый"
                              "field_creative_case" => "одиннадцатым"
                              "field_dative_case" => "одиннадцатому"
                              "field_genitive_case" => "одинадцатого"
                              "field_nominative_case" => "одинадцатый"
                              "field_prepositional_case" => "одиннадцатом"
                            ]
                            "field_translit" => "odinadcatyj"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1241
                      #items: array:1 [
                        0 => App\Models\Term {#1242
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #original: array:6 [
                            "id" => 5158
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Илекса"
                            "field_cases" => null
                            "field_translit" => "ileksa"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1243
                      #items: array:3 [
                        0 => App\Models\Term {#1244
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4102
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Гельфгат"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Илья"
                            "field_patronymic" => "Маркович"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4102
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Гельфгат"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Илья"
                            "field_patronymic" => "Маркович"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        1 => App\Models\Term {#1245
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4104
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Генденштейн"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Лев"
                            "field_patronymic" => "Элевич"
                            "field_surname_rp" => "Генденштейна"
                          ]
                          #original: array:12 [
                            "id" => 4104
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Генденштейн"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Лев"
                            "field_patronymic" => "Элевич"
                            "field_surname_rp" => "Генденштейна"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                        2 => App\Models\Term {#1246
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4583
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кирик"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Леонид"
                            "field_patronymic" => "Анатольевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4583
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Кирик"
                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Леонид"
                            "field_patronymic" => "Анатольевич"
                            "field_surname_rp" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1247
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1248
                      #items: array:1 [
                        0 => App\Models\Term {#1249
                          #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" => 6518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Задачник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "задачник"
                              "field_creative_case" => "задачником"
                              "field_dative_case" => "задачнику"
                              "field_genitive_case" => "задачника"
                              "field_nominative_case" => "задачник"
                              "field_prepositional_case" => "задачнике"
                            ]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "zadachnik"
                          ]
                          #original: array:10 [
                            "id" => 6518
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Задачник"
                            "field_book_type_foreign" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "задачник"
                              "field_creative_case" => "задачником"
                              "field_dative_case" => "задачнику"
                              "field_genitive_case" => "задачника"
                              "field_nominative_case" => "задачник"
                              "field_prepositional_case" => "задачнике"
                            ]
                            "field_plural_form" => null
                            "field_short_name" => null
                            "field_short_name_foreign" => null
                            "field_translit" => "zadachnik"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1250
                      #items: array:1 [
                        0 => App\Models\Term {#1251
                          #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 {#1252
                      #items: array:1 [
                        0 => App\Models\Term {#1253
                          #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 {#1254
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1255
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1256
                      #items: array:1 [
                        0 => App\Models\Term {#1257
                          #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" => 40
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "профильный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "профильный"
                              "field_creative_case" => "профильным"
                              "field_dative_case" => "профильному"
                              "field_genitive_case" => "профильного"
                              "field_nominative_case" => "профильный"
                              "field_prepositional_case" => "профильном"
                            ]
                            "field_translit" => "profilnyy"
                          ]
                          #original: array:6 [
                            "id" => 40
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "профильный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "профильный"
                              "field_creative_case" => "профильным"
                              "field_dative_case" => "профильному"
                              "field_genitive_case" => "профильного"
                              "field_nominative_case" => "профильный"
                              "field_prepositional_case" => "профильном"
                            ]
                            "field_translit" => "profilnyy"
                          ]
                          #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_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1258
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1259
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1260
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
                    "field_publication_year" => "2008"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебное издание"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "459"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                        "alt" => ""
                        "width" => "1566"
                        "height" => "2412"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1261
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1262
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1263
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1264
                      #items: array:1 [
                        0 => App\Models\Term {#1265
                          #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" => 46
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "красный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "красный"
                              "field_creative_case" => "красным"
                              "field_dative_case" => "красному"
                              "field_genitive_case" => "красного"
                              "field_nominative_case" => "красный"
                              "field_prepositional_case" => "красном"
                            ]
                            "field_translit" => "krasnyy"
                          ]
                          #original: array:6 [
                            "id" => 46
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "красный"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "красный"
                              "field_creative_case" => "красным"
                              "field_dative_case" => "красному"
                              "field_genitive_case" => "красного"
                              "field_nominative_case" => "красный"
                              "field_prepositional_case" => "красном"
                            ]
                            "field_translit" => "krasnyy"
                          ]
                          #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" => 381
                      "subject" => 556
                      "class_subject" => 494
                    ]
                  ]
                  #original: array:50 [
                    "id" => 5400
                    "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 {#1237}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1238}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1241}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1243}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1247}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1248}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1250}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1252}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1254}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1255}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1256}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1258}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1259}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1260}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
                    "field_publication_year" => "2008"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебное издание"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "459"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                        "alt" => ""
                        "width" => "1566"
                        "height" => "2412"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1261}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1262}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1263}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1264}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 381
                      "subject" => 556
                      "class_subject" => 494
                    ]
                  ]
                  #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 {#1266
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319266
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Механика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1234}
            "field_page_start" => "6"
            "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 {#1268}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1266}
          ]
          #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 {#1267
          #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" => 1319303
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Механические колебания и волны"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1269
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "88"
            "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 {#1270
              #items: array:1 [
                0 => App\Models\Book {#1235}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1271
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319303
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Механические колебания и волны"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1269}
            "field_page_start" => "88"
            "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 {#1270}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1271}
          ]
          #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 {#1272
          #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" => 1319304
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "12. Механические колебания"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1273
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "88"
            "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 {#1274
              #items: array:1 [
                0 => App\Models\Book {#1235}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1316
              #items: array:1 [
                0 => App\Models\Branch {#1275
                  #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" => 1319303
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Механические колебания и волны"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1277
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "88"
                    "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 {#1276
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1309
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319303
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Механические колебания и волны"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1277}
                    "field_page_start" => "88"
                    "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 {#1276}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1309}
                  ]
                  #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" => 1319304
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "12. Механические колебания"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1273}
            "field_page_start" => "88"
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            "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 {#1274}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1316}
          ]
          #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\Branch {#1314
          #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" => 1319305
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1315
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "88"
            "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 {#1317
              #items: array:1 [
                0 => App\Models\Book {#1235}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1394
              #items: array:1 [
                0 => App\Models\Branch {#1318
                  #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" => 1319304
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "12. Механические колебания"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1320
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "88"
                    "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 {#1319
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1352
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319304
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "12. Механические колебания"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1320}
                    "field_page_start" => "88"
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                    "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 {#1319}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1352}
                  ]
                  #changes: []
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                  #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" => 1319305
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1315}
            "field_page_start" => "88"
            "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 {#1317}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1394}
          ]
          #changes: []
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          #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 {#1147
      #items: array:2 [
        0 => App\Models\Element {#1219
          #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" => 1493762
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1209
              #items: array:1 [
                0 => App\Models\Edition {#1217
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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            "text" => "<p><strong>12.7.</strong> Два одинаковых математических маятника длиной $\text{l}$ связаны невесомой пружиной жесткостью $\text{k}$. На рисунке показано положение равновесия системы. Маятники отклоняют (в плоскости рисунка) на одинаковые по величине углы и отпускают.</p><p>Найдите период $\text{T}$ малых колебаний связанных маятников, если: а) маятники отклонены в одну сторону (колебания в одной фазе); б) маятники отклонены в противоположные стороны (колебания в противофазе).</p><p>☑ а) $T = 2\pi\sqrt{\frac{l}{g}}$; б) $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.</p><p><strong><em>Решение.</em></strong> <strong>а)</strong> Пружина не деформируется при колебаниях, так что сила упругости не возникает (связь между маятниками «не работает»). Поэтому оба маятника колеблются независимо друг от друга с одним и тем же периодом $T = 2\pi\sqrt{\frac{l}{g}}$.</p><p><strong>б)</strong> Если каждый из маятников отклонился от положения равновесия на величину $\text{x}$, то деформация пружины равна $2x$, а энергия системы</p><p>$E = \frac{k(2x)^2}{2} + 2\frac{mgx^2}{2l} + 2\frac{mv^2}{2} = \left(2k + \frac{mg}{l}\right)x^2 + m(x')^2.$</p><p>Отсюда $T = 2\pi\sqrt{\frac{m}{2k + \frac{mg}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.</p>"
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            "text" => "<p><strong>12.7.</strong> Два одинаковых математических маятника длиной $\text{l}$ связаны невесомой пружиной жесткостью $\text{k}$. На рисунке показано положение равновесия системы. Маятники отклоняют (в плоскости рисунка) на одинаковые по величине углы и отпускают.</p><p>Найдите период $\text{T}$ малых колебаний связанных маятников, если: а) маятники отклонены в одну сторону (колебания в одной фазе); б) маятники отклонены в противоположные стороны (колебания в противофазе).</p><p>☑ а) $T = 2\pi\sqrt{\frac{l}{g}}$; б) $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.</p><p><strong><em>Решение.</em></strong> <strong>а)</strong> Пружина не деформируется при колебаниях, так что сила упругости не возникает (связь между маятниками «не работает»). Поэтому оба маятника колеблются независимо друг от друга с одним и тем же периодом $T = 2\pi\sqrt{\frac{l}{g}}$.</p><p><strong>б)</strong> Если каждый из маятников отклонился от положения равновесия на величину $\text{x}$, то деформация пружины равна $2x$, а энергия системы</p><p>$E = \frac{k(2x)^2}{2} + 2\frac{mgx^2}{2l} + 2\frac{mv^2}{2} = \left(2k + \frac{mg}{l}\right)x^2 + m(x')^2.$</p><p>Отсюда $T = 2\pi\sqrt{\frac{m}{2k + \frac{mg}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>Два одинаковых математических маятника</p><p>Длина нити: $l$</p><p>Масса груза: $m$</p><p>Жесткость пружины: $k$</p><p>Колебания считаются малыми.</p><p><strong>Найти:</strong></p><p>Период малых колебаний $T$, если:</p><p>а) маятники отклонены в одну сторону (колебания в одной фазе);</p><p>б) маятники отклонены в противоположные стороны (колебания в противофазе).</p><p><strong>Решение:</strong></p><p><strong>а) маятники отклонены в одну сторону (колебания в одной фазе)</strong></p><p>Когда оба маятника отклоняются на одинаковое малое расстояние в одну и ту же сторону, расстояние между грузами маятников остается постоянным и равным длине недеформированной пружины. Следовательно, пружина не деформируется, и сила упругости, которую она создает, равна нулю. В этом случае связь между маятниками "не работает", и каждый из них колеблется независимо от другого как обычный математический маятник.</p><p>Период малых колебаний математического маятника определяется формулой:</p><p>$T = 2\pi\sqrt{\frac{l}{g}}$</p><p>где $l$ – длина маятника, а $g$ – ускорение свободного падения.</p><p><strong>Ответ:</strong> $T = 2\pi\sqrt{\frac{l}{g}}$</p><p><strong>б) маятники отклонены в противоположные стороны (колебания в противофазе)</strong></p><p>Когда маятники отклоняются на одинаковое малое расстояние $x$ от положения равновесия в противоположные стороны, пружина растягивается (или сжимается) на величину $\Delta l_{пр} = x - (-x) = 2x$.</p><p>Рассмотрим силы, действующие на один из маятников (например, левый) в горизонтальном направлении, которые создают возвращающий эффект. Для малых колебаний это:</p><p><strong>1.</strong> Проекция силы тяжести: $F_g = -mg \sin\alpha$. При малых углах $\sin\alpha \approx \frac{x}{l}$, поэтому $F_g \approx -\frac{mg}{l}x$.</p><p><strong>2.</strong> Сила упругости пружины: $F_{упр} = -k \Delta l_{пр} = -k(2x) = -2kx$.</p><p>Полная возвращающая сила, действующая на маятник, равна сумме этих сил:</p><p>$F_{возвр} = F_g + F_{упр} = -\frac{mg}{l}x - 2kx = -(\frac{mg}{l} + 2k)x$.</p><p>Это уравнение показывает, что возвращающая сила пропорциональна смещению $x$, а значит, колебания являются гармоническими. Эффективный коэффициент жесткости системы для одного маятника равен $K_{эфф} = \frac{mg}{l} + 2k$.</p><p>Согласно второму закону Ньютона, $m\ddot{x} = F_{возвр}$, где $\ddot{x}$ - ускорение.</p><p>$m\ddot{x} = -(\frac{mg}{l} + 2k)x$.</p><p>Период гармонических колебаний находится по формуле $T = 2\pi\sqrt{\frac{m}{K_{эфф}}}$. Подставим наше значение $K_{эфф}$:</p><p>$T = 2\pi\sqrt{\frac{m}{\frac{mg}{l} + 2k}}$</p><p>Преобразуем выражение под корнем, приведя знаменатель к общему делителю:</p><p>$T = 2\pi\sqrt{\frac{m}{\frac{mg + 2kl}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$</p><p><strong>Ответ:</strong> $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>Два одинаковых математических маятника</p><p>Длина нити: $l$</p><p>Масса груза: $m$</p><p>Жесткость пружины: $k$</p><p>Колебания считаются малыми.</p><p><strong>Найти:</strong></p><p>Период малых колебаний $T$, если:</p><p>а) маятники отклонены в одну сторону (колебания в одной фазе);</p><p>б) маятники отклонены в противоположные стороны (колебания в противофазе).</p><p><strong>Решение:</strong></p><p><strong>а) маятники отклонены в одну сторону (колебания в одной фазе)</strong></p><p>Когда оба маятника отклоняются на одинаковое малое расстояние в одну и ту же сторону, расстояние между грузами маятников остается постоянным и равным длине недеформированной пружины. Следовательно, пружина не деформируется, и сила упругости, которую она создает, равна нулю. В этом случае связь между маятниками "не работает", и каждый из них колеблется независимо от другого как обычный математический маятник.</p><p>Период малых колебаний математического маятника определяется формулой:</p><p>$T = 2\pi\sqrt{\frac{l}{g}}$</p><p>где $l$ – длина маятника, а $g$ – ускорение свободного падения.</p><p><strong>Ответ:</strong> $T = 2\pi\sqrt{\frac{l}{g}}$</p><p><strong>б) маятники отклонены в противоположные стороны (колебания в противофазе)</strong></p><p>Когда маятники отклоняются на одинаковое малое расстояние $x$ от положения равновесия в противоположные стороны, пружина растягивается (или сжимается) на величину $\Delta l_{пр} = x - (-x) = 2x$.</p><p>Рассмотрим силы, действующие на один из маятников (например, левый) в горизонтальном направлении, которые создают возвращающий эффект. Для малых колебаний это:</p><p><strong>1.</strong> Проекция силы тяжести: $F_g = -mg \sin\alpha$. При малых углах $\sin\alpha \approx \frac{x}{l}$, поэтому $F_g \approx -\frac{mg}{l}x$.</p><p><strong>2.</strong> Сила упругости пружины: $F_{упр} = -k \Delta l_{пр} = -k(2x) = -2kx$.</p><p>Полная возвращающая сила, действующая на маятник, равна сумме этих сил:</p><p>$F_{возвр} = F_g + F_{упр} = -\frac{mg}{l}x - 2kx = -(\frac{mg}{l} + 2k)x$.</p><p>Это уравнение показывает, что возвращающая сила пропорциональна смещению $x$, а значит, колебания являются гармоническими. Эффективный коэффициент жесткости системы для одного маятника равен $K_{эфф} = \frac{mg}{l} + 2k$.</p><p>Согласно второму закону Ньютона, $m\ddot{x} = F_{возвр}$, где $\ddot{x}$ - ускорение.</p><p>$m\ddot{x} = -(\frac{mg}{l} + 2k)x$.</p><p>Период гармонических колебаний находится по формуле $T = 2\pi\sqrt{\frac{m}{K_{эфф}}}$. Подставим наше значение $K_{эфф}$:</p><p>$T = 2\pi\sqrt{\frac{m}{\frac{mg}{l} + 2k}}$</p><p>Преобразуем выражение под корнем, приведя знаменатель к общему делителю:</p><p>$T = 2\pi\sqrt{\frac{m}{\frac{mg + 2kl}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$</p><p><strong>Ответ:</strong> $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$</p>"
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№12.7 (с. 90)
Условие. №12.7 (с. 90)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 90, номер 12.7, Условие
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 90, номер 12.7, Условие (продолжение 2)

12.7. Два одинаковых математических маятника длиной $\text{l}$ связаны невесомой пружиной жесткостью $\text{k}$. На рисунке показано положение равновесия системы. Маятники отклоняют (в плоскости рисунка) на одинаковые по величине углы и отпускают.

Найдите период $\text{T}$ малых колебаний связанных маятников, если: а) маятники отклонены в одну сторону (колебания в одной фазе); б) маятники отклонены в противоположные стороны (колебания в противофазе).

☑ а) $T = 2\pi\sqrt{\frac{l}{g}}$; б) $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.

Решение. а) Пружина не деформируется при колебаниях, так что сила упругости не возникает (связь между маятниками «не работает»). Поэтому оба маятника колеблются независимо друг от друга с одним и тем же периодом $T = 2\pi\sqrt{\frac{l}{g}}$.

б) Если каждый из маятников отклонился от положения равновесия на величину $\text{x}$, то деформация пружины равна $2x$, а энергия системы

$E = \frac{k(2x)^2}{2} + 2\frac{mgx^2}{2l} + 2\frac{mv^2}{2} = \left(2k + \frac{mg}{l}\right)x^2 + m(x')^2.$

Отсюда $T = 2\pi\sqrt{\frac{m}{2k + \frac{mg}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$.

Решение. №12.7 (с. 90)

Дано:

Два одинаковых математических маятника

Длина нити: $l$

Масса груза: $m$

Жесткость пружины: $k$

Колебания считаются малыми.

Найти:

Период малых колебаний $T$, если:

а) маятники отклонены в одну сторону (колебания в одной фазе);

б) маятники отклонены в противоположные стороны (колебания в противофазе).

Решение:

а) маятники отклонены в одну сторону (колебания в одной фазе)

Когда оба маятника отклоняются на одинаковое малое расстояние в одну и ту же сторону, расстояние между грузами маятников остается постоянным и равным длине недеформированной пружины. Следовательно, пружина не деформируется, и сила упругости, которую она создает, равна нулю. В этом случае связь между маятниками "не работает", и каждый из них колеблется независимо от другого как обычный математический маятник.

Период малых колебаний математического маятника определяется формулой:

$T = 2\pi\sqrt{\frac{l}{g}}$

где $l$ – длина маятника, а $g$ – ускорение свободного падения.

Ответ: $T = 2\pi\sqrt{\frac{l}{g}}$

б) маятники отклонены в противоположные стороны (колебания в противофазе)

Когда маятники отклоняются на одинаковое малое расстояние $x$ от положения равновесия в противоположные стороны, пружина растягивается (или сжимается) на величину $\Delta l_{пр} = x - (-x) = 2x$.

Рассмотрим силы, действующие на один из маятников (например, левый) в горизонтальном направлении, которые создают возвращающий эффект. Для малых колебаний это:

1. Проекция силы тяжести: $F_g = -mg \sin\alpha$. При малых углах $\sin\alpha \approx \frac{x}{l}$, поэтому $F_g \approx -\frac{mg}{l}x$.

2. Сила упругости пружины: $F_{упр} = -k \Delta l_{пр} = -k(2x) = -2kx$.

Полная возвращающая сила, действующая на маятник, равна сумме этих сил:

$F_{возвр} = F_g + F_{упр} = -\frac{mg}{l}x - 2kx = -(\frac{mg}{l} + 2k)x$.

Это уравнение показывает, что возвращающая сила пропорциональна смещению $x$, а значит, колебания являются гармоническими. Эффективный коэффициент жесткости системы для одного маятника равен $K_{эфф} = \frac{mg}{l} + 2k$.

Согласно второму закону Ньютона, $m\ddot{x} = F_{возвр}$, где $\ddot{x}$ - ускорение.

$m\ddot{x} = -(\frac{mg}{l} + 2k)x$.

Период гармонических колебаний находится по формуле $T = 2\pi\sqrt{\frac{m}{K_{эфф}}}$. Подставим наше значение $K_{эфф}$:

$T = 2\pi\sqrt{\frac{m}{\frac{mg}{l} + 2k}}$

Преобразуем выражение под корнем, приведя знаменатель к общему делителю:

$T = 2\pi\sqrt{\frac{m}{\frac{mg + 2kl}{l}}} = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$

Ответ: $T = 2\pi\sqrt{\frac{ml}{mg + 2kl}}$

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