Номер 13.5, страница 98 - 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. 13. Механические волны. Звук. Упражнения - номер 13.5, страница 98.

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 {#1167
                      #items: array:1 [
                        0 => App\Models\Term {#1168
                          #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 {#1169
                      #items: array:3 [
                        0 => App\Models\Term {#1170
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1171
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1172
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1173
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1174
                      #items: array:1 [
                        0 => App\Models\Term {#1175
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1176
                      #items: array:1 [
                        0 => App\Models\Term {#1177
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1178
                      #items: array:1 [
                        0 => App\Models\Term {#1179
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array: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 {#1180
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1181
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1182
                      #items: array:1 [
                        0 => App\Models\Term {#1183
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "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 {#1184
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1185
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186
                      #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 {#1187
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1188
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1189
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1190
                      #items: array:1 [
                        0 => App\Models\Term {#1191
                          #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 {#1163}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1164}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1167}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1169}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1173}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1174}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1176}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1178}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1180}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1181}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1182}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1184}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1185}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1186}
                    "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 {#1187}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1188}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1189}
                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1190}
                    "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 {#1192
              #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 {#1160}
            "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 {#1194}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1192}
          ]
          #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 {#1193
          #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 {#1195
              #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 {#1196
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1197
              #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 {#1195}
            "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 {#1196}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1197}
          ]
          #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 {#1198
          #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" => 1319307
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "13. Механические волны. Звук"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1199
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "97"
            "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 {#1200
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1242
              #items: array:1 [
                0 => App\Models\Branch {#1201
                  #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 {#1203
                      #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 {#1202
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1235
                      #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 {#1203}
                    "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 {#1202}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1235}
                  ]
                  #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" => 1319307
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "13. Механические волны. Звук"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1199}
            "field_page_start" => "97"
            "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 {#1200}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1242}
          ]
          #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 {#1240
          #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" => 1319308
            "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 {#1241
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "97"
            "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 {#1243
              #items: array:1 [
                0 => App\Models\Book {#1161}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1252
              #items: array:1 [
                0 => App\Models\Branch {#1251
                  #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" => 1319307
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "13. Механические волны. Звук"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1253
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "97"
                    "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 {#1254
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1255
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1319307
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "13. Механические волны. Звук"
                    "field_branch_order" => null
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1253}
                    "field_page_start" => "97"
                    "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 {#1254}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1255}
                  ]
                  #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" => 1319308
            "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 {#1241}
            "field_page_start" => "97"
            "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 {#1243}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1252}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1108
      #items: array:2 [
        0 => App\Models\Element {#1138
          #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" => 1493768
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1128
              #items: array:1 [
                0 => App\Models\Edition {#1137
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
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            "text" => "<p><strong>13.5.</strong> Над цилиндрическим сосудом высотой $H = 1 \text{ м}$ звучит камертон с частотой колебаний $\nu = 340 \text{ Гц}$. В сосуд медленно наливают воду. При каких положениях уровня воды в сосуде звучание камертона значительно усиливается?</p><p>☑ <strong>При уровне воды 25 см или 75 см.</strong></p><p><strong><em>Решение.</em></strong> Усиление звука происходит в случае резонанса — когда частота звука совпадает с собственной частотой колебаний воздушного столба в сосуде. У поверхности воды при этом находится узел, а у верхнего открытого края сосуда — пучность стоячей волны. Расстояние между ближайшими узлами равно $\lambda/2$, а между узлом и ближайшей пучностью $\lambda/4$. Поэтому длина воздушного столба должна равняться $\lambda/4 + k \cdot \lambda/2$, где $k = 0, 1, 2,...$, а $\lambda = \nu/v = 1 \text{ м}$ ($\text{v}$ — скорость звука в воздухе). При заданных в условии числовых данных это соотношение может выполняться лишь при $k = 0$ и $k = 1$, т. е. высота столба воды равна 25 см или 75 см.</p>"
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          #original: array:7 [
            "id" => 1493768
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1128}
            "task" => array:2 [
              "refs" => "1319535"
              "type" => "task"
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            "text" => "<p><strong>13.5.</strong> Над цилиндрическим сосудом высотой $H = 1 \text{ м}$ звучит камертон с частотой колебаний $\nu = 340 \text{ Гц}$. В сосуд медленно наливают воду. При каких положениях уровня воды в сосуде звучание камертона значительно усиливается?</p><p>☑ <strong>При уровне воды 25 см или 75 см.</strong></p><p><strong><em>Решение.</em></strong> Усиление звука происходит в случае резонанса — когда частота звука совпадает с собственной частотой колебаний воздушного столба в сосуде. У поверхности воды при этом находится узел, а у верхнего открытого края сосуда — пучность стоячей волны. Расстояние между ближайшими узлами равно $\lambda/2$, а между узлом и ближайшей пучностью $\lambda/4$. Поэтому длина воздушного столба должна равняться $\lambda/4 + k \cdot \lambda/2$, где $k = 0, 1, 2,...$, а $\lambda = \nu/v = 1 \text{ м}$ ($\text{v}$ — скорость звука в воздухе). При заданных в условии числовых данных это соотношение может выполняться лишь при $k = 0$ и $k = 1$, т. е. высота столба воды равна 25 см или 75 см.</p>"
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            "created_at" => "2026-04-10 13:58:26"
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            "edition" => Illuminate\Database\Eloquent\Collection {#1122
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                    "created_at" => "2026-04-10 13:58:26"
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                    "title" => "Решение"
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                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1126
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                    "id" => 6138
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            "text" => "<p><strong>Дано:</strong></p><p>Высота цилиндрического сосуда, $H = 1$ м</p><p>Частота колебаний камертона, $ν = 340$ Гц</p><p>Скорость звука в воздухе, $v ≈ 340$ м/с</p><p><strong>Найти:</strong></p><p>Уровни воды в сосуде $h$, при которых звучание камертона значительно усиливается.</p><p><strong>Решение:</strong></p><p>Значительное усиление звука происходит в результате явления акустического резонанса. Резонанс возникает, когда собственная частота колебаний воздушного столба в сосуде совпадает с частотой звуковой волны, создаваемой камертоном.</p><p>Воздушный столб в сосуде, частично заполненном водой, можно рассматривать как резонатор, который является трубой, закрытой с одного конца (поверхность воды) и открытой с другого (верхний край сосуда). В такой трубе могут возникать стоячие волны. При этом у закрытого конца (поверхности воды) всегда будет узел смещения, а у открытого конца — пучность смещения.</p><p>Условием возникновения резонанса является размещение на длине воздушного столба $L$ нечетного числа четвертей длин волн. Математически это выражается формулой:</p><p>$L = (2k + 1) \frac{λ}{4}$, где $k = 0, 1, 2, ...$ — целое неотрицательное число, а $λ$ — длина волны звука.</p><p>Длину волны можно найти из соотношения:</p><p>$λ = \frac{v}{ν}$</p><p>Подставим данные из условия задачи. Скорость звука в воздухе примем равной 340 м/с.</p><p>$λ = \frac{340 \text{ м/с}}{340 \text{ Гц}} = 1$ м</p><p>Теперь найдем возможные длины воздушного столба $L$, при которых будет наблюдаться резонанс. Длина воздушного столба $L$ ограничена высотой сосуда $H$:</p><p>$L ≤ H$</p><p>$(2k + 1) \frac{λ}{4} ≤ H$</p><p>$(2k + 1) \frac{1 \text{ м}}{4} ≤ 1 \text{ м}$</p><p>$2k + 1 ≤ 4$</p><p>$2k ≤ 3$</p><p>$k ≤ 1.5$</p><p>Так как $k$ — целое неотрицательное число, возможны следующие значения: $k = 0$ и $k = 1$.</p><p>Рассчитаем соответствующие длины воздушного столба $L$ для этих значений $k$:</p><p><strong>1.</strong> При $k = 0$ (основной тон):</p><p>$L_1 = (2 \cdot 0 + 1) \frac{1}{4} = 0.25$ м</p><p><strong>2.</strong> При $k = 1$ (первый обертон):</p><p>$L_2 = (2 \cdot 1 + 1) \frac{1}{4} = \frac{3}{4} = 0.75$ м</p><p>Уровень воды в сосуде $h$ связан с высотой сосуда $H$ и длиной воздушного столба $L$ соотношением $h = H - L$. Найдем соответствующие уровни воды:</p><p><strong>1.</strong> Для $L_1 = 0.25$ м:</p><p>$h_1 = 1 \text{ м} - 0.25 \text{ м} = 0.75$ м, что соответствует 75 см.</p><p><strong>2.</strong> Для $L_2 = 0.75$ м:</p><p>$h_2 = 1 \text{ м} - 0.75 \text{ м} = 0.25$ м, что соответствует 25 см.</p><p><strong>Ответ:</strong> Звучание камертона значительно усиливается при уровнях воды в сосуде 25 см и 75 см.</p>"
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            "id" => 1691325
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1122}
            "task" => array:2 [
              "refs" => "1319535"
              "type" => "task"
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            "text" => "<p><strong>Дано:</strong></p><p>Высота цилиндрического сосуда, $H = 1$ м</p><p>Частота колебаний камертона, $ν = 340$ Гц</p><p>Скорость звука в воздухе, $v ≈ 340$ м/с</p><p><strong>Найти:</strong></p><p>Уровни воды в сосуде $h$, при которых звучание камертона значительно усиливается.</p><p><strong>Решение:</strong></p><p>Значительное усиление звука происходит в результате явления акустического резонанса. Резонанс возникает, когда собственная частота колебаний воздушного столба в сосуде совпадает с частотой звуковой волны, создаваемой камертоном.</p><p>Воздушный столб в сосуде, частично заполненном водой, можно рассматривать как резонатор, который является трубой, закрытой с одного конца (поверхность воды) и открытой с другого (верхний край сосуда). В такой трубе могут возникать стоячие волны. При этом у закрытого конца (поверхности воды) всегда будет узел смещения, а у открытого конца — пучность смещения.</p><p>Условием возникновения резонанса является размещение на длине воздушного столба $L$ нечетного числа четвертей длин волн. Математически это выражается формулой:</p><p>$L = (2k + 1) \frac{λ}{4}$, где $k = 0, 1, 2, ...$ — целое неотрицательное число, а $λ$ — длина волны звука.</p><p>Длину волны можно найти из соотношения:</p><p>$λ = \frac{v}{ν}$</p><p>Подставим данные из условия задачи. Скорость звука в воздухе примем равной 340 м/с.</p><p>$λ = \frac{340 \text{ м/с}}{340 \text{ Гц}} = 1$ м</p><p>Теперь найдем возможные длины воздушного столба $L$, при которых будет наблюдаться резонанс. Длина воздушного столба $L$ ограничена высотой сосуда $H$:</p><p>$L ≤ H$</p><p>$(2k + 1) \frac{λ}{4} ≤ H$</p><p>$(2k + 1) \frac{1 \text{ м}}{4} ≤ 1 \text{ м}$</p><p>$2k + 1 ≤ 4$</p><p>$2k ≤ 3$</p><p>$k ≤ 1.5$</p><p>Так как $k$ — целое неотрицательное число, возможны следующие значения: $k = 0$ и $k = 1$.</p><p>Рассчитаем соответствующие длины воздушного столба $L$ для этих значений $k$:</p><p><strong>1.</strong> При $k = 0$ (основной тон):</p><p>$L_1 = (2 \cdot 0 + 1) \frac{1}{4} = 0.25$ м</p><p><strong>2.</strong> При $k = 1$ (первый обертон):</p><p>$L_2 = (2 \cdot 1 + 1) \frac{1}{4} = \frac{3}{4} = 0.75$ м</p><p>Уровень воды в сосуде $h$ связан с высотой сосуда $H$ и длиной воздушного столба $L$ соотношением $h = H - L$. Найдем соответствующие уровни воды:</p><p><strong>1.</strong> Для $L_1 = 0.25$ м:</p><p>$h_1 = 1 \text{ м} - 0.25 \text{ м} = 0.75$ м, что соответствует 75 см.</p><p><strong>2.</strong> Для $L_2 = 0.75$ м:</p><p>$h_2 = 1 \text{ м} - 0.75 \text{ м} = 0.25$ м, что соответствует 25 см.</p><p><strong>Ответ:</strong> Звучание камертона значительно усиливается при уровнях воды в сосуде 25 см и 75 см.</p>"
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                    "created_at" => "2026-04-10 13:58:26"
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№13.5 (с. 98)
Условие. №13.5 (с. 98)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 98, номер 13.5, Условие

13.5. Над цилиндрическим сосудом высотой $H = 1 \text{ м}$ звучит камертон с частотой колебаний $\nu = 340 \text{ Гц}$. В сосуд медленно наливают воду. При каких положениях уровня воды в сосуде звучание камертона значительно усиливается?

При уровне воды 25 см или 75 см.

Решение. Усиление звука происходит в случае резонанса — когда частота звука совпадает с собственной частотой колебаний воздушного столба в сосуде. У поверхности воды при этом находится узел, а у верхнего открытого края сосуда — пучность стоячей волны. Расстояние между ближайшими узлами равно $\lambda/2$, а между узлом и ближайшей пучностью $\lambda/4$. Поэтому длина воздушного столба должна равняться $\lambda/4 + k \cdot \lambda/2$, где $k = 0, 1, 2,...$, а $\lambda = \nu/v = 1 \text{ м}$ ($\text{v}$ — скорость звука в воздухе). При заданных в условии числовых данных это соотношение может выполняться лишь при $k = 0$ и $k = 1$, т. е. высота столба воды равна 25 см или 75 см.

Решение. №13.5 (с. 98)

Дано:

Высота цилиндрического сосуда, $H = 1$ м

Частота колебаний камертона, $ν = 340$ Гц

Скорость звука в воздухе, $v ≈ 340$ м/с

Найти:

Уровни воды в сосуде $h$, при которых звучание камертона значительно усиливается.

Решение:

Значительное усиление звука происходит в результате явления акустического резонанса. Резонанс возникает, когда собственная частота колебаний воздушного столба в сосуде совпадает с частотой звуковой волны, создаваемой камертоном.

Воздушный столб в сосуде, частично заполненном водой, можно рассматривать как резонатор, который является трубой, закрытой с одного конца (поверхность воды) и открытой с другого (верхний край сосуда). В такой трубе могут возникать стоячие волны. При этом у закрытого конца (поверхности воды) всегда будет узел смещения, а у открытого конца — пучность смещения.

Условием возникновения резонанса является размещение на длине воздушного столба $L$ нечетного числа четвертей длин волн. Математически это выражается формулой:

$L = (2k + 1) \frac{λ}{4}$, где $k = 0, 1, 2, ...$ — целое неотрицательное число, а $λ$ — длина волны звука.

Длину волны можно найти из соотношения:

$λ = \frac{v}{ν}$

Подставим данные из условия задачи. Скорость звука в воздухе примем равной 340 м/с.

$λ = \frac{340 \text{ м/с}}{340 \text{ Гц}} = 1$ м

Теперь найдем возможные длины воздушного столба $L$, при которых будет наблюдаться резонанс. Длина воздушного столба $L$ ограничена высотой сосуда $H$:

$L ≤ H$

$(2k + 1) \frac{λ}{4} ≤ H$

$(2k + 1) \frac{1 \text{ м}}{4} ≤ 1 \text{ м}$

$2k + 1 ≤ 4$

$2k ≤ 3$

$k ≤ 1.5$

Так как $k$ — целое неотрицательное число, возможны следующие значения: $k = 0$ и $k = 1$.

Рассчитаем соответствующие длины воздушного столба $L$ для этих значений $k$:

1. При $k = 0$ (основной тон):

$L_1 = (2 \cdot 0 + 1) \frac{1}{4} = 0.25$ м

2. При $k = 1$ (первый обертон):

$L_2 = (2 \cdot 1 + 1) \frac{1}{4} = \frac{3}{4} = 0.75$ м

Уровень воды в сосуде $h$ связан с высотой сосуда $H$ и длиной воздушного столба $L$ соотношением $h = H - L$. Найдем соответствующие уровни воды:

1. Для $L_1 = 0.25$ м:

$h_1 = 1 \text{ м} - 0.25 \text{ м} = 0.75$ м, что соответствует 75 см.

2. Для $L_2 = 0.75$ м:

$h_2 = 1 \text{ м} - 0.75 \text{ м} = 0.25$ м, что соответствует 25 см.

Ответ: Звучание камертона значительно усиливается при уровнях воды в сосуде 25 см и 75 см.

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