Номер 11.11, страница 81 - 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. Законы сохранения в механике. 11. Механическая работа. Энергия. Закон сохранения энергии. Упражнения - номер 11.11, страница 81.

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                            "name" => "11"
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                              "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 {#1128
                      #items: array:1 [
                        0 => App\Models\Term {#1129
                          #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 {#1130
                      #items: array:3 [
                        0 => App\Models\Term {#1131
                          #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 {#1132
                          #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 {#1133
                          #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 {#1134
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1135
                      #items: array:1 [
                        0 => 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: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 {#1137
                      #items: array:1 [
                        0 => App\Models\Term {#1138
                          #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 {#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: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 {#1141
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1142
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => 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" => 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 {#1145
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1146
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1147
                      #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 {#1148
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1149
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1150
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1151
                      #items: array:1 [
                        0 => App\Models\Term {#1152
                          #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 {#1124}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1125}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1128}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1130}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1134}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1135}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1137}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1139}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1141}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1142}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1143}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1145}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1146}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1147}
                    "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 {#1148}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1149}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1150}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1151}
                    "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: []
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                  #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 {#1153
              #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 {#1121}
            "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 {#1155}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1153}
          ]
          #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 {#1154
          #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" => 1319296
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Законы сохранения в механике"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1156
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "73"
            "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 {#1157
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1158
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319296
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Законы сохранения в механике"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1156}
            "field_page_start" => "73"
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            "field_metatags_description" => null
            "field_h1" => null
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            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1157}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1158}
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => 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" => 1319300
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "11. Механическая работа. Энергия. Закон сохранения энергии"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1160
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "77"
            "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 {#1161
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1170
              #items: array:1 [
                0 => App\Models\Branch {#1169
                  #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" => 1319296
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Законы сохранения в механике"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1171
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "73"
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                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1172
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1173
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                  ]
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1171}
                    "field_page_start" => "73"
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                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1173}
                  ]
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                  #dateFormat: null
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
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          ]
          #original: array:24 [
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            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "11. Механическая работа. Энергия. Закон сохранения энергии"
            "field_branch_order" => null
            "field_url" => null
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            "field_branch_covers" => []
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          ]
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          #dateFormat: null
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            0 => "*"
          ]
        }
        3 => App\Models\Branch {#1163
          #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" => 1319301
            "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 {#1162
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "77"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
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            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
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            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1166
              #items: array:1 [
                0 => App\Models\Book {#1122}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1179
              #items: array:1 [
                0 => App\Models\Branch {#1178
                  #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" => 1319300
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "11. Механическая работа. Энергия. Закон сохранения энергии"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1180
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "77"
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                    "field_h1" => null
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                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1181
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1182
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                  ]
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                    "created_at" => "2026-04-10 13:58:26"
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1180}
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                    "field_h1" => null
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                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1181}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1182}
                  ]
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                  #touches: []
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                  #hidden: []
                  #visible: []
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
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          ]
          #original: array:24 [
            "id" => 1319301
            "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 {#1162}
            "field_page_start" => "77"
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            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
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            "field_metatags_description" => null
            "field_h1" => null
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            "field_description_bottom" => null
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            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1166}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1179}
          ]
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          +timestamps: true
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          #visible: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1072
      #items: array:2 [
        0 => App\Models\Element {#1101
          #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" => 1493753
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1091
              #items: array:1 [
                0 => App\Models\Edition {#1100
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                    "id" => 5430
                    "created_at" => "2026-04-10 13:58:26"
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                    "title" => "Условие"
                    "field_order" => "1"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1097
                      #items: array:1 [ …1]
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                    "id" => 5430
                    "created_at" => "2026-04-10 13:58:26"
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                    "title" => "Условие"
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            "task" => array:2 [
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            "text" => "<p><strong>11.11.</strong> Санки съезжают с горы, длина основания которой $a = 5 \text{ м}$, а высота $H = 2 \text{ м}$, и проезжают до остановки еще $s = 35 \text{ м}$ по горизонтальной площадке. Найдите коэффициент трения, считая его одинаковым на всем пути. Переход склона горы в горизонтальную поверхность считайте плавным.</p><p>&#9745; $\mu = 0,05$.</p><p><strong>Решение.</strong> Кинетическая энергия санок равна нулю как в начале, так и в конце пути. Значит, начальная потенциальная энергия санок $mgH$ целиком расходуется на работу против силы трения (потенциальная энергия переходит во внутреннюю энергию). Поскольку сила трения на склоне с углом наклона $\alpha$ равна $\mu mg \cos \alpha$, а на горизонтальном участке она равна $\mu mg$, получаем: $mgH = \mu mg \cos \alpha \cdot L + \mu mg \cdot s$.</p><p>Здесь $\text{L}$ — длина склона горы. Учитывая, что $L \cos \alpha = a$, находим $\mu = H / (a + s) = 0,05$.</p>"
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              0 => array:5 [
                "name" => "11-1.jpg"
                "alt" => null
                "width" => "1387"
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                "path" => "/media/fizika_10/gelfgat-z/0-11/11-1.webp?ts=1756251036"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 1493753
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1091}
            "task" => array:2 [
              "refs" => "1319508"
              "type" => "task"
            ]
            "text" => "<p><strong>11.11.</strong> Санки съезжают с горы, длина основания которой $a = 5 \text{ м}$, а высота $H = 2 \text{ м}$, и проезжают до остановки еще $s = 35 \text{ м}$ по горизонтальной площадке. Найдите коэффициент трения, считая его одинаковым на всем пути. Переход склона горы в горизонтальную поверхность считайте плавным.</p><p>&#9745; $\mu = 0,05$.</p><p><strong>Решение.</strong> Кинетическая энергия санок равна нулю как в начале, так и в конце пути. Значит, начальная потенциальная энергия санок $mgH$ целиком расходуется на работу против силы трения (потенциальная энергия переходит во внутреннюю энергию). Поскольку сила трения на склоне с углом наклона $\alpha$ равна $\mu mg \cos \alpha$, а на горизонтальном участке она равна $\mu mg$, получаем: $mgH = \mu mg \cos \alpha \cdot L + \mu mg \cdot s$.</p><p>Здесь $\text{L}$ — длина склона горы. Учитывая, что $L \cos \alpha = a$, находим $\mu = H / (a + s) = 0,05$.</p>"
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          +exists: true
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            "id" => 1691310
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1085
              #items: array:1 [
                0 => App\Models\Edition {#1094
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
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                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
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                  #attributes: array:21 [
                    "id" => 6138
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение"
                    "field_order" => "2"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1089
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
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                    "field_page_content_text_checked" => "0"
                    "field_solution_author" => "Gemini 2.5 Pro"
                    "field_moderator" => "tolik"
                    "field_edition_type" => "solution"
                    "field_root_dir" => "1-"
                    "field_responsible" => Illuminate\Database\Eloquent\Collection {#1090
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                      #items: []
                      #escapeWhenCastingToString: false
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                    "field_process_formula" => "katex"
                    "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1084
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                    "id" => 6138
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "title" => "Решение"
                    "field_order" => "2"
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1089}
                    "field_content_type" => "free"
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                    "field_solution_author" => "Gemini 2.5 Pro"
                    "field_moderator" => "tolik"
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                    "field_comment" => null
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            "task" => array:2 [
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              "type" => "task"
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            "text" => "<p><strong>Дано:</strong></p><p>Длина основания горы: $a = 5$ м</p><p>Высота горы: $H = 2$ м</p><p>Путь по горизонтальной площадке: $s = 35$ м</p><p>Начальная скорость: $v_0 = 0$ м/с</p><p>Конечная скорость: $v_k = 0$ м/с</p><p>Ускорение свободного падения: $g \approx 9.8$ м/с²</p><p>Все величины представлены в системе СИ.</p><p><strong>Найти:</strong></p><p>Коэффициент трения: $\mu$</p><p><strong>Решение:</strong></p><p>Применим закон изменения механической энергии. Изменение полной механической энергии системы равно работе всех неконсервативных сил. В данном случае, это работа силы трения $A_{тр}$.</p><p>$\Delta E = E_{кон} - E_{нач} = A_{тр}$</p><p>Начальная энергия системы (санки на вершине горы) состоит только из потенциальной энергии, так как санки начинают движение из состояния покоя:</p><p>$E_{нач} = E_п = mgH$</p><p>Конечная энергия системы (санки остановились на горизонтальной площадке) равна нулю, так как и высота, и скорость равны нулю:</p><p>$E_{кон} = 0$</p><p>Таким образом, изменение энергии: $\Delta E = 0 - mgH = -mgH$.</p><p>Работа силы трения совершается на двух участках: на склоне горы ($A_{тр1}$) и на горизонтальной поверхности ($A_{тр2}$).</p><p><strong>1.</strong> Работа трения на склоне. Сила трения на склоне равна $F_{тр1} = \mu N_1$, где $N_1$ - сила нормальной реакции. На наклонной плоскости $N_1 = mg\cos\alpha$, где $\alpha$ - угол наклона горы. Работа совершается на пути $L$ (длина склона):</p><p>$A_{тр1} = -F_{тр1} \cdot L = -\mu mg L \cos\alpha$</p><p>Из геометрии прямоугольного треугольника, образованного высотой $H$, основанием $a$ и склоном $L$, следует, что $L \cos\alpha = a$. Тогда работа трения на склоне:</p><p>$A_{тр1} = -\mu mg a$</p><p><strong>2.</strong> Работа трения на горизонтальном участке. Сила трения на горизонтальной поверхности равна $F_{тр2} = \mu N_2 = \mu mg$. Работа совершается на пути $s$:</p><p>$A_{тр2} = -F_{тр2} \cdot s = -\mu mg s$</p><p>Суммарная работа силы трения:</p><p>$A_{тр} = A_{тр1} + A_{тр2} = -\mu mg a - \mu mg s = -\mu mg (a+s)$</p><p>Теперь приравняем изменение механической энергии и работу силы трения:</p><p>$-mgH = -\mu mg (a+s)$</p><p>Сократим обе части уравнения на $-mg$:</p><p>$H = \mu (a+s)$</p><p>Отсюда выразим искомый коэффициент трения $\mu$:</p><p>$\mu = \frac{H}{a+s}$</p><p>Подставим числовые значения:</p><p>$\mu = \frac{2}{5 + 35} = \frac{2}{40} = 0.05$</p><p><strong>Ответ:</strong></p><p>$\mu = 0.05$.</p>"
          ]
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            "id" => 1691310
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1085}
            "task" => array:2 [
              "refs" => "1319508"
              "type" => "task"
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            "text" => "<p><strong>Дано:</strong></p><p>Длина основания горы: $a = 5$ м</p><p>Высота горы: $H = 2$ м</p><p>Путь по горизонтальной площадке: $s = 35$ м</p><p>Начальная скорость: $v_0 = 0$ м/с</p><p>Конечная скорость: $v_k = 0$ м/с</p><p>Ускорение свободного падения: $g \approx 9.8$ м/с²</p><p>Все величины представлены в системе СИ.</p><p><strong>Найти:</strong></p><p>Коэффициент трения: $\mu$</p><p><strong>Решение:</strong></p><p>Применим закон изменения механической энергии. Изменение полной механической энергии системы равно работе всех неконсервативных сил. В данном случае, это работа силы трения $A_{тр}$.</p><p>$\Delta E = E_{кон} - E_{нач} = A_{тр}$</p><p>Начальная энергия системы (санки на вершине горы) состоит только из потенциальной энергии, так как санки начинают движение из состояния покоя:</p><p>$E_{нач} = E_п = mgH$</p><p>Конечная энергия системы (санки остановились на горизонтальной площадке) равна нулю, так как и высота, и скорость равны нулю:</p><p>$E_{кон} = 0$</p><p>Таким образом, изменение энергии: $\Delta E = 0 - mgH = -mgH$.</p><p>Работа силы трения совершается на двух участках: на склоне горы ($A_{тр1}$) и на горизонтальной поверхности ($A_{тр2}$).</p><p><strong>1.</strong> Работа трения на склоне. Сила трения на склоне равна $F_{тр1} = \mu N_1$, где $N_1$ - сила нормальной реакции. На наклонной плоскости $N_1 = mg\cos\alpha$, где $\alpha$ - угол наклона горы. Работа совершается на пути $L$ (длина склона):</p><p>$A_{тр1} = -F_{тр1} \cdot L = -\mu mg L \cos\alpha$</p><p>Из геометрии прямоугольного треугольника, образованного высотой $H$, основанием $a$ и склоном $L$, следует, что $L \cos\alpha = a$. Тогда работа трения на склоне:</p><p>$A_{тр1} = -\mu mg a$</p><p><strong>2.</strong> Работа трения на горизонтальном участке. Сила трения на горизонтальной поверхности равна $F_{тр2} = \mu N_2 = \mu mg$. Работа совершается на пути $s$:</p><p>$A_{тр2} = -F_{тр2} \cdot s = -\mu mg s$</p><p>Суммарная работа силы трения:</p><p>$A_{тр} = A_{тр1} + A_{тр2} = -\mu mg a - \mu mg s = -\mu mg (a+s)$</p><p>Теперь приравняем изменение механической энергии и работу силы трения:</p><p>$-mgH = -\mu mg (a+s)$</p><p>Сократим обе части уравнения на $-mg$:</p><p>$H = \mu (a+s)$</p><p>Отсюда выразим искомый коэффициент трения $\mu$:</p><p>$\mu = \frac{H}{a+s}$</p><p>Подставим числовые значения:</p><p>$\mu = \frac{2}{5 + 35} = \frac{2}{40} = 0.05$</p><p><strong>Ответ:</strong></p><p>$\mu = 0.05$.</p>"
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                    "id" => 1519587
                    "created_at" => "2026-04-10 13:58:26"
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                    "edition" => Illuminate\Database\Eloquent\Collection {#1115}
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№11.11 (с. 81)
Условие. №11.11 (с. 81)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 81, номер 11.11, Условие

11.11. Санки съезжают с горы, длина основания которой $a = 5 \text{ м}$, а высота $H = 2 \text{ м}$, и проезжают до остановки еще $s = 35 \text{ м}$ по горизонтальной площадке. Найдите коэффициент трения, считая его одинаковым на всем пути. Переход склона горы в горизонтальную поверхность считайте плавным.

☑ $\mu = 0,05$.

Решение. Кинетическая энергия санок равна нулю как в начале, так и в конце пути. Значит, начальная потенциальная энергия санок $mgH$ целиком расходуется на работу против силы трения (потенциальная энергия переходит во внутреннюю энергию). Поскольку сила трения на склоне с углом наклона $\alpha$ равна $\mu mg \cos \alpha$, а на горизонтальном участке она равна $\mu mg$, получаем: $mgH = \mu mg \cos \alpha \cdot L + \mu mg \cdot s$.

Здесь $\text{L}$ — длина склона горы. Учитывая, что $L \cos \alpha = a$, находим $\mu = H / (a + s) = 0,05$.

Решение. №11.11 (с. 81)

Дано:

Длина основания горы: $a = 5$ м

Высота горы: $H = 2$ м

Путь по горизонтальной площадке: $s = 35$ м

Начальная скорость: $v_0 = 0$ м/с

Конечная скорость: $v_k = 0$ м/с

Ускорение свободного падения: $g \approx 9.8$ м/с²

Все величины представлены в системе СИ.

Найти:

Коэффициент трения: $\mu$

Решение:

Применим закон изменения механической энергии. Изменение полной механической энергии системы равно работе всех неконсервативных сил. В данном случае, это работа силы трения $A_{тр}$.

$\Delta E = E_{кон} - E_{нач} = A_{тр}$

Начальная энергия системы (санки на вершине горы) состоит только из потенциальной энергии, так как санки начинают движение из состояния покоя:

$E_{нач} = E_п = mgH$

Конечная энергия системы (санки остановились на горизонтальной площадке) равна нулю, так как и высота, и скорость равны нулю:

$E_{кон} = 0$

Таким образом, изменение энергии: $\Delta E = 0 - mgH = -mgH$.

Работа силы трения совершается на двух участках: на склоне горы ($A_{тр1}$) и на горизонтальной поверхности ($A_{тр2}$).

1. Работа трения на склоне. Сила трения на склоне равна $F_{тр1} = \mu N_1$, где $N_1$ - сила нормальной реакции. На наклонной плоскости $N_1 = mg\cos\alpha$, где $\alpha$ - угол наклона горы. Работа совершается на пути $L$ (длина склона):

$A_{тр1} = -F_{тр1} \cdot L = -\mu mg L \cos\alpha$

Из геометрии прямоугольного треугольника, образованного высотой $H$, основанием $a$ и склоном $L$, следует, что $L \cos\alpha = a$. Тогда работа трения на склоне:

$A_{тр1} = -\mu mg a$

2. Работа трения на горизонтальном участке. Сила трения на горизонтальной поверхности равна $F_{тр2} = \mu N_2 = \mu mg$. Работа совершается на пути $s$:

$A_{тр2} = -F_{тр2} \cdot s = -\mu mg s$

Суммарная работа силы трения:

$A_{тр} = A_{тр1} + A_{тр2} = -\mu mg a - \mu mg s = -\mu mg (a+s)$

Теперь приравняем изменение механической энергии и работу силы трения:

$-mgH = -\mu mg (a+s)$

Сократим обе части уравнения на $-mg$:

$H = \mu (a+s)$

Отсюда выразим искомый коэффициент трения $\mu$:

$\mu = \frac{H}{a+s}$

Подставим числовые значения:

$\mu = \frac{2}{5 + 35} = \frac{2}{40} = 0.05$

Ответ:

$\mu = 0.05$.

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