Номер 8, страница 77 - гдз по физике 9 класс учебник Изергин

Физика, 9 класс Учебник, автор: Изергин Эдуард Тимофеевич, издательство Русское слово, Москва, 2019

Авторы: Изергин Э. Т.

Тип: Учебник

Серия: инновационная школа

Издательство: Русское слово

Год издания: 2019 - 2026

Цвет обложки: синий

ISBN: 978-5-533-01069-6

Глава III. Механические колебания и волны. Параграф 15. Центростремительное ускорение - номер 8, страница 77.

App\Models\Task {#1024 // resources/views/models/task/default.blade.php
  #connection: "mysql"
  #table: "tasks"
  #primaryKey: "id"
  #keyType: "int"
  +incrementing: true
  #with: []
  #withCount: []
  +preventsLazyLoading: false
  #perPage: 15
  +exists: true
  +wasRecentlyCreated: false
  #escapeWhenCastingToString: false
  #attributes: array:24 [
    "id" => 1439742
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "77"
    "field_page_end" => null
    "field_url" => "/9-klass/fizika/izergin-uchebnik/15-8"
    "field_display_title" => "8"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#331
      #items: array:1 [
        0 => App\Models\Term {#1029
          #connection: "mysql"
          #table: "terms"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: false
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #original: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "field_metatags_title" => null
    "field_metatags_description" => null
    "field_h1" => null
    "field_description_top" => null
    "field_description_bottom" => null
    "field_match" => null
    "breadcrumbs" => []
    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1026
      #items: []
      #escapeWhenCastingToString: false
    }
    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#342
      #items: array:1 [
        0 => App\Models\Branch {#1023
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 1439560
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Механические колебания и волны"
            "field_branch_order" => "III"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#333
              #items: array:1 [
                0 => App\Models\Term {#1033
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Главу"
                      "field_creative_case" => "Главой"
                      "field_dative_case" => "Главе"
                      "field_genitive_case" => "Главы"
                      "field_nominative_case" => "Глава"
                      "field_prepositional_case" => "Главе"
                    ]
                    "field_page_check_not_needed" => null
                    "field_short_name" => null
                  ]
                  #original: array:7 [
                    "id" => 29
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Глава"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Главу"
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                      "field_genitive_case" => "Главы"
                      "field_nominative_case" => "Глава"
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                    ]
                    "field_page_check_not_needed" => null
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                  ]
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                    0 => "*"
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              ]
              #escapeWhenCastingToString: false
            }
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            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
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            "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 {#1030
              #items: array:1 [
                0 => App\Models\Book {#1032
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
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                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 4169
                    "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 {#1034
                      #items: array:1 [
                        0 => App\Models\Term {#1035
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6493
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Физика"
                            "field_abbreviated_name" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "физику"
                              "field_creative_case" => "физикой"
                              "field_dative_case" => "физике"
                              "field_genitive_case" => "физики"
                              "field_nominative_case" => "физика"
                              "field_prepositional_case" => "физике"
                            ]
                            "field_foreign_lang_name" => null
                            "field_short_name" => null
                            "field_subject_type" => "technical_subject"
                            "field_translit" => "fizika"
                          ]
                          #original: array:10 [
                            "id" => 6493
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Физика"
                            "field_abbreviated_name" => null
                            "field_cases" => array:6 [
                              "field_accusative_case" => "физику"
                              "field_creative_case" => "физикой"
                              "field_dative_case" => "физике"
                              "field_genitive_case" => "физики"
                              "field_nominative_case" => "физика"
                              "field_prepositional_case" => "физике"
                            ]
                            "field_foreign_lang_name" => null
                            "field_short_name" => null
                            "field_subject_type" => "technical_subject"
                            "field_translit" => "fizika"
                          ]
                          #changes: []
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                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
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                          #hidden: []
                          #visible: []
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                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1036
                      #items: array:1 [
                        0 => App\Models\Term {#1037
                          #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" => 5458
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "9"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "девятый"
                              "field_creative_case" => "девятым"
                              "field_dative_case" => "девятому"
                              "field_genitive_case" => "девятого"
                              "field_nominative_case" => "девятый"
                              "field_prepositional_case" => "девятом"
                            ]
                            "field_translit" => "devjatyj"
                          ]
                          #original: array:6 [
                            "id" => 5458
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "9"
                            "field_cases" => array:6 [
                              "field_accusative_case" => "девятый"
                              "field_creative_case" => "девятым"
                              "field_dative_case" => "девятому"
                              "field_genitive_case" => "девятого"
                              "field_nominative_case" => "девятый"
                              "field_prepositional_case" => "девятом"
                            ]
                            "field_translit" => "devjatyj"
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
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                          #hidden: []
                          #visible: []
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                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1038
                      #items: array:1 [
                        0 => App\Models\Term {#1039
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
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                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 5176
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Русское слово"
                            "field_cases" => null
                            "field_translit" => "russkoe slovo"
                          ]
                          #original: array:6 [
                            "id" => 5176
                            "created_at" => "2026-04-10 13:58:26"
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                            "field_translit" => "russkoe slovo"
                          ]
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                          ]
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                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1040
                      #items: array:1 [
                        0 => App\Models\Term {#1041
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
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                          #escapeWhenCastingToString: false
                          #attributes: array:12 [
                            "id" => 4491
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
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                            "field_bio" => null
                            "field_degree_rp" => null
                            "field_foreign_lang_name" => null
                            "field_foreign_lang_patronymic" => null
                            "field_foreign_lang_surname" => null
                            "field_name" => "Эдуард"
                            "field_patronymic" => "Тимофеевич"
                            "field_surname_rp" => null
                          ]
                          #original: array:12 [
                            "id" => 4491
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "Изергин"
                            "field_bio" => null
                            "field_degree_rp" => null
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                            "field_foreign_lang_patronymic" => null
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                            "field_name" => "Эдуард"
                            "field_patronymic" => "Тимофеевич"
                            "field_surname_rp" => null
                          ]
                          #changes: []
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                      #items: []
                      #escapeWhenCastingToString: false
                    }
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                      #items: array:1 [
                        0 => App\Models\Term {#1044
                          #connection: "mysql"
                          #table: "terms"
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                          #attributes: array:10 [
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                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
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                            "field_book_type_foreign" => null
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                            ]
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                      #items: array:1 [
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                        0 => App\Models\Term {#1048
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                            ]
                            "field_translit" => "moskva"
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                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1049
                      #items: array:1 [
                        0 => App\Models\Term {#1050
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:8 [
                            "id" => 4715
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "инновационная школа"
                            "field_cases" => null
                            "field_foreign_lang_series" => null
                            "field_transcription_eng" => null
                            "field_translit" => "innovacionnaya shkola"
                          ]
                          #original: array:8 [
                            "id" => 4715
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "инновационная школа"
                            "field_cases" => null
                            "field_foreign_lang_series" => null
                            "field_transcription_eng" => null
                            "field_translit" => "innovacionnaya shkola"
                          ]
                          #changes: []
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                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
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                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1051
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1052
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1053
                      #items: array:1 [
                        0 => App\Models\Term {#1054
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #original: array:10 [
                            "id" => 6706
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "ФГОС (старый)"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_color" => null
                            "field_end_year" => "2022"
                            "field_start_year" => "2019"
                            "field_translit" => "fgos-old"
                            "field_type" => null
                          ]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [
                            0 => "*"
                          ]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1055
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для 9 класса общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "388"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/izergin-u/"
                    "field_isbn" => "978-5-533-01069-6"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                        "alt" => ""
                        "width" => "1881"
                        "height" => "2502"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1057
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1058
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1059
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1060
                      #items: array:1 [
                        0 => App\Models\Term {#1061
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [
                            "id" => 49
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "синий"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "siniy"
                          ]
                          #original: array:6 [
                            "id" => 49
                            "created_at" => "2026-04-10 13:58:26"
                            "updated_at" => null
                            "name" => "синий"
                            "field_cases" => array:6 [
                              "field_accusative_case" => null
                              "field_creative_case" => null
                              "field_dative_case" => null
                              "field_genitive_case" => null
                              "field_nominative_case" => null
                              "field_prepositional_case" => null
                            ]
                            "field_translit" => "siniy"
                          ]
                          #changes: []
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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
                    }
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #original: array:50 [
                    "id" => 4169
                    "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 {#1034}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1036}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1038}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1040}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1042}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1043}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1045}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1047}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1049}
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1051}
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1052}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1053}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1055}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1056}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => null
                    "field_publication_year" => "2019"
                    "field_publication_year_until" => null
                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебник для 9 класса общеобразовательных организаций"
                    "field_allowed" => null
                    "field_reserve_field" => null
                    "field_link_to_source" => null
                    "field_tasks_count" => "388"
                    "field_priority" => null
                    "field_default_folder" => "/fizika_09/izergin-u/"
                    "field_isbn" => "978-5-533-01069-6"
                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                        "alt" => ""
                        "width" => "1881"
                        "height" => "2502"
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1057}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1058}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1059}
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1060}
                    "field_metatags_title" => null
                    "field_metatags_description" => null
                    "field_h1" => null
                    "field_description_top" => null
                    "field_description_bottom" => null
                    "breadcrumbs" => array:3 [
                      "class" => 380
                      "subject" => 556
                      "class_subject" => 493
                    ]
                  ]
                  #changes: []
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                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1062
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1439560
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Механические колебания и волны"
            "field_branch_order" => "III"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#333}
            "field_page_start" => "67"
            "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 {#1030}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1062}
          ]
          #changes: []
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          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
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          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1063
      #items: array:2 [
        0 => App\Models\Branch {#1023}
        1 => App\Models\Branch {#1064
          #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" => 1439562
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Центростремительное ускорение"
            "field_branch_order" => "15"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1065
              #items: array:1 [
                0 => App\Models\Term {#1066
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Параграф"
                      "field_creative_case" => "Параграфом"
                      "field_dative_case" => "Параграфу"
                      "field_genitive_case" => "Параграфа"
                      "field_nominative_case" => "Параграф"
                      "field_prepositional_case" => "Параграфе"
                    ]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #original: array:7 [
                    "id" => 32
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Параграф"
                    "field_cases" => array:6 [
                      "field_accusative_case" => "Параграф"
                      "field_creative_case" => "Параграфом"
                      "field_dative_case" => "Параграфу"
                      "field_genitive_case" => "Параграфа"
                      "field_nominative_case" => "Параграф"
                      "field_prepositional_case" => "Параграфе"
                    ]
                    "field_page_check_not_needed" => null
                    "field_short_name" => "§"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "72"
            "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 {#1067
              #items: array:1 [
                0 => App\Models\Book {#1032}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1068
              #items: array:1 [
                0 => App\Models\Branch {#1069
                  #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" => 1439560
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Механические колебания и волны"
                    "field_branch_order" => "III"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070
                      #items: array:1 [
                        0 => App\Models\Term {#1033}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_page_start" => "67"
                    "field_branch_display" => "0"
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                    "field_display_branch_page" => "1"
                    "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
                    "field_branch_cover" => []
                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1071
                      #items: array:1 [
                        0 => App\Models\Book {#1032}
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1072
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                  ]
                  #original: array:24 [
                    "id" => 1439560
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_display_title" => "Механические колебания и волны"
                    "field_branch_order" => "III"
                    "field_url" => null
                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1070}
                    "field_page_start" => "67"
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                    "field_display_branch_page" => "1"
                    "field_branch_title_in_content" => "0"
                    "field_navigation_title" => null
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                    "book" => Illuminate\Database\Eloquent\Collection {#1071}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1072}
                  ]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #touches: []
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1439562
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Центростремительное ускорение"
            "field_branch_order" => "15"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1065}
            "field_page_start" => "72"
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            "field_navigation_title" => null
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            "field_h1" => null
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            "text" => "<p><strong>8.</strong> Каков наименьший радиус дуги для поворота автомобиля, движущейся по горизонтальной дороге со скоростью 36 км/ч, если коэффициент трения скольжения колёс о дорогу равен 0,25?</p>"
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            "task" => array:2 [
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            "text" => "<p><strong>8.</strong> Каков наименьший радиус дуги для поворота автомобиля, движущейся по горизонтальной дороге со скоростью 36 км/ч, если коэффициент трения скольжения колёс о дорогу равен 0,25?</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>Скорость автомашины, $v = 36$ км/ч</p><p>Коэффициент трения скольжения, $\mu = 0,25$</p><p>Ускорение свободного падения, $g \approx 10$ м/с<sup>2</sup></p><p>Перевод в систему СИ:</p><p>$v = 36 \cdot \frac{1000 \text{ м}}{3600 \text{ с}} = 10$ м/с</p><p><strong>Найти:</strong></p><p>Наименьший радиус дуги, $R_{min}$ - ?</p><p><strong>Решение:</strong></p><p>При движении автомобиля по дуге окружности (при повороте) на него действует центростремительная сила. Эту силу обеспечивает сила трения покоя между колесами и дорогой. Согласно второму закону Ньютона, в проекции на ось, направленную к центру окружности (радиальную ось), мы имеем:</p><p>$F_{тр} = m \cdot a_{ц}$</p><p>где $\text{m}$ - масса автомобиля, а $a_{ц}$ - его центростремительное ускорение.</p><p>Центростремительное ускорение вычисляется по формуле:</p><p>$a_{ц} = \frac{v^2}{R}$</p><p>где $\text{v}$ - скорость автомобиля, $\text{R}$ - радиус дуги.</p><p>Сила трения не может быть больше своего максимального значения. Максимальная сила трения покоя (которая удерживает автомобиль от заноса) определяется как:</p><p>$F_{тр.макс} = \mu \cdot N$</p><p>где $\text{N}$ - сила нормальной реакции опоры. Поскольку дорога горизонтальная, сила реакции опоры равна по модулю силе тяжести, действующей на автомобиль:</p><p>$N = m \cdot g$</p><p>Таким образом, максимальная сила трения равна:</p><p>$F_{тр.макс} = \mu mg$</p><p>Для того чтобы автомобиль совершил поворот без заноса, необходимо, чтобы требуемая центростремительная сила не превышала максимальную силу трения:</p><p>$m \frac{v^2}{R} \le \mu mg$</p><p>Наименьший радиус поворота $R_{min}$ соответствует предельному случаю, когда сила трения достигает своего максимального значения. В этом случае мы используем знак равенства:</p><p>$m \frac{v^2}{R_{min}} = \mu mg$</p><p>Массу автомобиля $\text{m}$ можно сократить в обеих частях уравнения:</p><p>$\frac{v^2}{R_{min}} = \mu g$</p><p>Отсюда выражаем наименьший радиус $R_{min}$:</p><p>$R_{min} = \frac{v^2}{\mu g}$</p><p>Подставим известные значения в формулу:</p><p>$R_{min} = \frac{(10 \text{ м/с})^2}{0,25 \cdot 10 \text{ м/с}^2} = \frac{100 \text{ м}^2/\text{с}^2}{2,5 \text{ м/с}^2} = 40$ м</p><p><strong>Ответ:</strong> наименьший радиус дуги для поворота автомашины равен 40 м.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>Скорость автомашины, $v = 36$ км/ч</p><p>Коэффициент трения скольжения, $\mu = 0,25$</p><p>Ускорение свободного падения, $g \approx 10$ м/с<sup>2</sup></p><p>Перевод в систему СИ:</p><p>$v = 36 \cdot \frac{1000 \text{ м}}{3600 \text{ с}} = 10$ м/с</p><p><strong>Найти:</strong></p><p>Наименьший радиус дуги, $R_{min}$ - ?</p><p><strong>Решение:</strong></p><p>При движении автомобиля по дуге окружности (при повороте) на него действует центростремительная сила. Эту силу обеспечивает сила трения покоя между колесами и дорогой. Согласно второму закону Ньютона, в проекции на ось, направленную к центру окружности (радиальную ось), мы имеем:</p><p>$F_{тр} = m \cdot a_{ц}$</p><p>где $\text{m}$ - масса автомобиля, а $a_{ц}$ - его центростремительное ускорение.</p><p>Центростремительное ускорение вычисляется по формуле:</p><p>$a_{ц} = \frac{v^2}{R}$</p><p>где $\text{v}$ - скорость автомобиля, $\text{R}$ - радиус дуги.</p><p>Сила трения не может быть больше своего максимального значения. Максимальная сила трения покоя (которая удерживает автомобиль от заноса) определяется как:</p><p>$F_{тр.макс} = \mu \cdot N$</p><p>где $\text{N}$ - сила нормальной реакции опоры. Поскольку дорога горизонтальная, сила реакции опоры равна по модулю силе тяжести, действующей на автомобиль:</p><p>$N = m \cdot g$</p><p>Таким образом, максимальная сила трения равна:</p><p>$F_{тр.макс} = \mu mg$</p><p>Для того чтобы автомобиль совершил поворот без заноса, необходимо, чтобы требуемая центростремительная сила не превышала максимальную силу трения:</p><p>$m \frac{v^2}{R} \le \mu mg$</p><p>Наименьший радиус поворота $R_{min}$ соответствует предельному случаю, когда сила трения достигает своего максимального значения. В этом случае мы используем знак равенства:</p><p>$m \frac{v^2}{R_{min}} = \mu mg$</p><p>Массу автомобиля $\text{m}$ можно сократить в обеих частях уравнения:</p><p>$\frac{v^2}{R_{min}} = \mu g$</p><p>Отсюда выражаем наименьший радиус $R_{min}$:</p><p>$R_{min} = \frac{v^2}{\mu g}$</p><p>Подставим известные значения в формулу:</p><p>$R_{min} = \frac{(10 \text{ м/с})^2}{0,25 \cdot 10 \text{ м/с}^2} = \frac{100 \text{ м}^2/\text{с}^2}{2,5 \text{ м/с}^2} = 40$ м</p><p><strong>Ответ:</strong> наименьший радиус дуги для поворота автомашины равен 40 м.</p>"
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                    "field_default_folder" => "/fizika_09/izergin-u/"
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                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
                    ]
                    "field_covers" => array:1 [
                      0 => array:4 [
                        "path" => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                        "alt" => ""
                        "width" => "1881"
                         …1
                      ]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1123
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                      #escapeWhenCastingToString: false
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1126
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                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1119}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1121}
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                    "field_cover" => array:1 [
                      0 => "/media/fizika_09/izergin-u/covers/cover1.webp?ts=1759162386"
                    ]
                    "field_cover_alts" => array:1 [
                      0 => ""
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                    "field_covers" => array:1 [
                      0 => array:4 [ …4]
                    ]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1123}
                    "field_new_book" => Illuminate\Database\Eloquent\Collection {#1124}
                    "field_old_book" => Illuminate\Database\Eloquent\Collection {#1125}
                    "field_url" => "/9-klass/fizika/izergin-uchebnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1126}
                    "field_metatags_title" => null
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                    0 => "*"
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                0 => App\Models\Element {#1130
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                  #attributes: array:6 [
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                    "created_at" => "2026-04-10 13:58:26"
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                    "edition" => Illuminate\Database\Eloquent\Collection {#1131
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                    "img" => array:1 [
                      0 => array:5 [ …5]
                    ]
                  ]
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                    "edition" => Illuminate\Database\Eloquent\Collection {#1131}
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                    "img" => array:1 [
                      0 => array:5 [ …5]
                    ]
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                    0 => "*"
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            "tasks" => Illuminate\Database\Eloquent\Collection {#1138
              #items: array:6 [
                0 => App\Models\Task {#1139
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                  #attributes: array:24 [
                    "id" => 1439737
                    "created_at" => "2026-04-10 13:58:26"
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                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1143
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                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1149
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                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1189
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                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
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                    ]
                    "previous" => array:2 [
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                      "type" => "task"
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                    "book" => Illuminate\Database\Eloquent\Collection {#1206
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                      #escapeWhenCastingToString: false
                    }
                    "page" => array:2 [
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                  ]
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                    "field_page_start" => "76"
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                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1142}
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                    "book" => Illuminate\Database\Eloquent\Collection {#1206}
                    "page" => array:2 [
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                  #dateFormat: null
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                  #touches: []
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                1 => App\Models\Task {#1207
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
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                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "field_page_start" => "77"
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                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1208
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                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1209
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1210
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1211
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1212
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                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
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                    ]
                    "previous" => array:2 [
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                      "type" => "task"
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                    "book" => Illuminate\Database\Eloquent\Collection {#1223
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                      #escapeWhenCastingToString: false
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                    "page" => array:2 [
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                    ]
                  ]
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                    "content" => Illuminate\Database\Eloquent\Collection {#1212}
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                    "book" => Illuminate\Database\Eloquent\Collection {#1223}
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                    0 => "*"
                  ]
                }
                2 => App\Models\Task {#1224
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
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                  #with: []
                  #withCount: []
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                  #attributes: array:24 [
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                    "created_at" => "2026-04-10 13:58:26"
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                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1225
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                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "breadcrumbs" => []
                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1226
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1227
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1228
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1229
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
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                      "type" => "task"
                    ]
                    "previous" => array:2 [
                      "refs" => "1439738"
                      "type" => "task"
                    ]
                    "book" => Illuminate\Database\Eloquent\Collection {#1246
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                      #escapeWhenCastingToString: false
                    }
                    "page" => array:2 [
                      "refs" => "1439395"
                      "type" => "book_page"
                    ]
                  ]
                  #original: array:24 [
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/15-5"
                    "field_display_title" => "5"
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                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1225}
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                    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1226}
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                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1228}
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                    "next" => array:2 [
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                    "book" => Illuminate\Database\Eloquent\Collection {#1246}
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                    0 => "*"
                  ]
                }
                3 => App\Models\Task {#1247
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
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                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
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                    "created_at" => "2026-04-10 13:58:26"
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                    "field_url" => "/9-klass/fizika/izergin-uchebnik/15-6"
                    "field_display_title" => "6"
                    "field_outside_task" => null
                    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1248
                      #items: array:1 [ …1]
                      #escapeWhenCastingToString: false
                    }
                    "field_metatags_title" => null
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                    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1250
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                      #escapeWhenCastingToString: false
                    }
                    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1251
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "content" => Illuminate\Database\Eloquent\Collection {#1252
                      #items: array:2 [ …2]
                      #escapeWhenCastingToString: false
                    }
                    "next" => array:2 [
                      "refs" => "1439741"
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                    ]
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                    "book" => Illuminate\Database\Eloquent\Collection {#1269
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                    "book" => Illuminate\Database\Eloquent\Collection {#1269}
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№8 (с. 77)
Условие. №8 (с. 77)
скриншот условия
Физика, 9 класс Учебник, автор: Изергин Эдуард Тимофеевич, издательство Русское слово, Москва, 2019, страница 77, номер 8, Условие

8. Каков наименьший радиус дуги для поворота автомобиля, движущейся по горизонтальной дороге со скоростью 36 км/ч, если коэффициент трения скольжения колёс о дорогу равен 0,25?

Решение. №8 (с. 77)

Дано:

Скорость автомашины, $v = 36$ км/ч

Коэффициент трения скольжения, $\mu = 0,25$

Ускорение свободного падения, $g \approx 10$ м/с2

Перевод в систему СИ:

$v = 36 \cdot \frac{1000 \text{ м}}{3600 \text{ с}} = 10$ м/с

Найти:

Наименьший радиус дуги, $R_{min}$ - ?

Решение:

При движении автомобиля по дуге окружности (при повороте) на него действует центростремительная сила. Эту силу обеспечивает сила трения покоя между колесами и дорогой. Согласно второму закону Ньютона, в проекции на ось, направленную к центру окружности (радиальную ось), мы имеем:

$F_{тр} = m \cdot a_{ц}$

где $\text{m}$ - масса автомобиля, а $a_{ц}$ - его центростремительное ускорение.

Центростремительное ускорение вычисляется по формуле:

$a_{ц} = \frac{v^2}{R}$

где $\text{v}$ - скорость автомобиля, $\text{R}$ - радиус дуги.

Сила трения не может быть больше своего максимального значения. Максимальная сила трения покоя (которая удерживает автомобиль от заноса) определяется как:

$F_{тр.макс} = \mu \cdot N$

где $\text{N}$ - сила нормальной реакции опоры. Поскольку дорога горизонтальная, сила реакции опоры равна по модулю силе тяжести, действующей на автомобиль:

$N = m \cdot g$

Таким образом, максимальная сила трения равна:

$F_{тр.макс} = \mu mg$

Для того чтобы автомобиль совершил поворот без заноса, необходимо, чтобы требуемая центростремительная сила не превышала максимальную силу трения:

$m \frac{v^2}{R} \le \mu mg$

Наименьший радиус поворота $R_{min}$ соответствует предельному случаю, когда сила трения достигает своего максимального значения. В этом случае мы используем знак равенства:

$m \frac{v^2}{R_{min}} = \mu mg$

Массу автомобиля $\text{m}$ можно сократить в обеих частях уравнения:

$\frac{v^2}{R_{min}} = \mu g$

Отсюда выражаем наименьший радиус $R_{min}$:

$R_{min} = \frac{v^2}{\mu g}$

Подставим известные значения в формулу:

$R_{min} = \frac{(10 \text{ м/с})^2}{0,25 \cdot 10 \text{ м/с}^2} = \frac{100 \text{ м}^2/\text{с}^2}{2,5 \text{ м/с}^2} = 40$ м

Ответ: наименьший радиус дуги для поворота автомашины равен 40 м.

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