Номер 6.5, страница 45 - 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. Динамика. 6. Сила упругости. Сила трения. Упражнения - номер 6.5, страница 45.

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            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1073}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1107}
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          #attributeCastCache: []
          #dateFormat: null
          #appends: []
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          #touches: []
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          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1108
          #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" => 1319280
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Динамика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "40"
            "field_branch_display" => "0"
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            "field_display_branch_in_title" => "1"
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            "field_navigation_title" => null
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            "field_h1" => null
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            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1110
              #items: array:1 [
                0 => App\Models\Book {#1111
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 5400
                    "created_at" => "2026-04-10 13:58:26"
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                    "field_subject" => Illuminate\Database\Eloquent\Collection {#1112 …2}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1114 …2}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1117 …2}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1119 …2}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1123 …2}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1124 …2}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1126 …2}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1128 …2}
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                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1134 …2}
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                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1135 …2}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1136 …2}
                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
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                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
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                    "field_cover_alts" => array:1 [ …1]
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                    "breadcrumbs" => array:3 [ …3]
                  ]
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                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1123 …2}
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                    "field_cover_description" => "лупа, парень едет на велосипеде"
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                    "field_default_folder" => "/fizika_10/gelfgat-z/"
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                    "field_cover" => array:1 [ …1]
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                    "breadcrumbs" => array:3 [ …3]
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                    0 => "*"
                  ]
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              ]
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                0 => App\Models\Branch {#1143
                  #connection: "mysql"
                  #table: "branches"
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                  +incrementing: true
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                  #escapeWhenCastingToString: false
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                    "id" => 1319266
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                    "book" => Illuminate\Database\Eloquent\Collection {#1145 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1146 …2}
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                    "id" => 1319266
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1144 …2}
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                    "book" => Illuminate\Database\Eloquent\Collection {#1145 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1146 …2}
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                  +timestamps: true
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
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          ]
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            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Динамика"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109}
            "field_page_start" => "40"
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            "field_branch_cover" => []
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            "book" => Illuminate\Database\Eloquent\Collection {#1110}
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          #hidden: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Branch {#1147
          #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" => 1319284
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "6. Сила упругости. Сила трения"
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            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1148
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "44"
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            "book" => Illuminate\Database\Eloquent\Collection {#1149
              #items: array:1 [
                0 => App\Models\Book {#1150
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
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                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [
                    "id" => 5400
                    "created_at" => "2026-04-10 13:58:26"
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                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1156 …2}
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                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1162 …2}
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                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1174 …2}
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                    "field_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
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                    "field_part" => ""
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                    "field_for_whom" => "Учебное издание"
                    "field_allowed" => null
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                    "field_tasks_count" => "459"
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                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [ …1]
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                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1179 …2}
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                  ]
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                  ]
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                    0 => "*"
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              ]
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            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1181
              #items: array:1 [
                0 => App\Models\Branch {#1182
                  #connection: "mysql"
                  #table: "branches"
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                  #keyType: "int"
                  +incrementing: true
                  #with: []
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                  #perPage: 15
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                  #escapeWhenCastingToString: false
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            "task" => array:2 [
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            "text" => "<p><strong>6.5.</strong> Два груза массами $M_1$ и $M_2$, связанные шнуром, лежат на горизонтальной поверхности. Шнур выдерживает силу натяжения $\text{T}$. Коэффициент трения между каждым из грузов и поверхностью равен $\mu$. С какой постоянной силой $\text{F}$ можно тянуть первый груз параллельно шнуру, чтобы шнур не разорвался?</p><p>$F &lt; T + \mu M_1 g$ при $T &lt; \mu M_2 g$; $F &lt; T(1 + M_1/M_2)$ при $T &gt; \mu M_2 g$.</p><p><strong><em>Решение.</em></strong> Если сила $\text{F}$ совсем мала, шнур даже не натянется: чтобы он натянулся, надо сначала сдвинуть с места первый груз, а это произойдет только при $F &gt; \mu M_1 g$. Что будет при дальнейшем увеличении $\text{F}$? Если шнур недостаточно прочный $(T &lt; \mu M_2 g)$, то он порвется еще до того, как сдвинется с места второй груз, при $F_{max} = T + \mu M_1 g$. Если же шнур достаточно прочный, то силу $\text{F}$ можно увеличивать без опасности разрыва шнура до тех пор, пока ускорение системы не достигнет максимального значения</p><p>$a_{max} = \frac{T - \mu M_2 g}{M_2}$.</p><p>При этом $F_{max} = (M_1 + M_2)(a_{max} + \mu g) = T(1 + \frac{M_1}{M_2})$.</p>"
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                "height" => 1247
                "path" => "/media/fizika_10/gelfgat-z/0-06/5-1.webp?ts=1756251021"
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            "text" => "<p><strong>6.5.</strong> Два груза массами $M_1$ и $M_2$, связанные шнуром, лежат на горизонтальной поверхности. Шнур выдерживает силу натяжения $\text{T}$. Коэффициент трения между каждым из грузов и поверхностью равен $\mu$. С какой постоянной силой $\text{F}$ можно тянуть первый груз параллельно шнуру, чтобы шнур не разорвался?</p><p>$F &lt; T + \mu M_1 g$ при $T &lt; \mu M_2 g$; $F &lt; T(1 + M_1/M_2)$ при $T &gt; \mu M_2 g$.</p><p><strong><em>Решение.</em></strong> Если сила $\text{F}$ совсем мала, шнур даже не натянется: чтобы он натянулся, надо сначала сдвинуть с места первый груз, а это произойдет только при $F &gt; \mu M_1 g$. Что будет при дальнейшем увеличении $\text{F}$? Если шнур недостаточно прочный $(T &lt; \mu M_2 g)$, то он порвется еще до того, как сдвинется с места второй груз, при $F_{max} = T + \mu M_1 g$. Если же шнур достаточно прочный, то силу $\text{F}$ можно увеличивать без опасности разрыва шнура до тех пор, пока ускорение системы не достигнет максимального значения</p><p>$a_{max} = \frac{T - \mu M_2 g}{M_2}$.</p><p>При этом $F_{max} = (M_1 + M_2)(a_{max} + \mu g) = T(1 + \frac{M_1}{M_2})$.</p>"
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            "text" => "<p><strong>Дано:</strong></p><p>Масса первого груза: $M_1$</p><p>Масса второго груза: $M_2$</p><p>Максимальная сила натяжения, которую выдерживает шнур: $T$</p><p>Коэффициент трения между грузами и поверхностью: $\mu$</p><p>Ускорение свободного падения: $g$</p><p><strong>Найти:</strong></p><p>Условие для силы $F$, при котором шнур не разорвется.</p><p><strong>Решение:</strong></p><p>Рассмотрим силы, действующие на грузы. На каждый груз действует сила тяжести, сила нормальной реакции опоры и сила трения. Сила трения скольжения (или максимальная сила трения покоя) для первого груза равна $F_{тр1} = \mu N_1 = \mu M_1 g$, а для второго $F_{тр2} = \mu N_2 = \mu M_2 g$.</p><p>Чтобы система пришла в движение, приложенная сила $F$ должна как минимум преодолеть силу трения покоя первого груза, то есть $F &gt; F_{тр1} = \mu M_1 g$. При этом шнур натянется. Обозначим силу натяжения шнура как $T'$. Шнур не разорвется, пока $T' \le T$.</p><p>Возможны два принципиально разных случая, в зависимости от прочности шнура $T$ и силы трения второго груза $F_{тр2}$.</p><p><strong>1.</strong> Случай, когда шнур "недостаточно прочный": $T \le \mu M_2 g$</p><p>В этом случае максимальная сила натяжения, которую выдерживает шнур ($T$), меньше или равна силе, необходимой для того, чтобы сдвинуть с места второй груз ($\mu M_2 g$). Это означает, что шнур порвется еще до того, как второй груз начнет движение. Разрыв произойдет в тот момент, когда сила натяжения $T'$ достигнет своего предельного значения $T$. В этот момент на первый груз действуют: приложенная сила $F$, сила натяжения $T$ (направлена против $F$) и сила трения $F_{тр1}$ (также против $F$).</p><p>Поскольку второй груз не движется, ускорение первого груза в момент разрыва можно считать равным нулю (предельный случай, когда груз вот-вот начнет ускоряться или движется равномерно). Тогда по первому закону Ньютона для первого груза:</p><p>$F_{max} - T - F_{тр1} = 0$</p><p>$F_{max} = T + F_{тр1} = T + \mu M_1 g$</p><p>Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:</p><p>$F &lt; T + \mu M_1 g$</p><p><strong>2.</strong> Случай, когда шнур "достаточно прочный": $T &gt; \mu M_2 g$</p><p>В этом случае шнур способен выдержать натяжение, необходимое для преодоления силы трения второго груза. Значит, при достаточно большой силе $F$ оба груза будут двигаться с одинаковым ускорением $a$.</p><p>Запишем второй закон Ньютона для каждого груза в проекции на горизонтальную ось:</p><p>Для второго груза ($M_2$): $T' - F_{тр2} = M_2 a \implies T' - \mu M_2 g = M_2 a$</p><p>Для первого груза ($M_1$): $F - T' - F_{тр1} = M_1 a \implies F - T' - \mu M_1 g = M_1 a$</p><p>Шнур разорвется, когда сила натяжения $T'$ достигнет максимального значения $T$. Найдем максимальное ускорение $a_{max}$, при котором это произойдет, из уравнения для второго груза:</p><p>$T - \mu M_2 g = M_2 a_{max} \implies a_{max} = \frac{T - \mu M_2 g}{M_2}$</p><p>Теперь найдем максимальную силу $F_{max}$, которая создает это ускорение. Проще всего рассмотреть систему из двух грузов как единое целое с массой $(M_1 + M_2)$.</p><p>$F_{max} - F_{тр1} - F_{тр2} = (M_1 + M_2)a_{max}$</p><p>$F_{max} - \mu M_1 g - \mu M_2 g = (M_1 + M_2)a_{max}$</p><p>$F_{max} = \mu(M_1 + M_2)g + (M_1 + M_2)a_{max}$</p><p>Подставим выражение для $a_{max}$:</p><p>$F_{max} = (M_1 + M_2)(\mu g + a_{max}) = (M_1 + M_2)\left(\mu g + \frac{T - \mu M_2 g}{M_2}\right)$</p><p>Приведем к общему знаменателю выражение в скобках:</p><p>$F_{max} = (M_1 + M_2)\left(\frac{\mu g M_2 + T - \mu M_2 g}{M_2}\right) = (M_1 + M_2)\frac{T}{M_2}$</p><p>$F_{max} = T\left(\frac{M_1 + M_2}{M_2}\right) = T\left(1 + \frac{M_1}{M_2}\right)$</p><p>Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:</p><p>$F &lt; T\left(1 + \frac{M_1}{M_2}\right)$</p><p><strong>Ответ:</strong></p><p>Чтобы шнур не разорвался, приложенная сила $F$ должна удовлетворять одному из двух условий в зависимости от прочности шнура:</p><p><strong>1.</strong> Если $T \le \mu M_2 g$, то $F &lt; T + \mu M_1 g$.</p><p><strong>2.</strong> Если $T &gt; \mu M_2 g$, то $F &lt; T\left(1 + \frac{M_1}{M_2}\right)$.</p>"
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            "id" => 1691273
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            "edition" => Illuminate\Database\Eloquent\Collection {#1296}
            "task" => array:2 [
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              "type" => "task"
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            "text" => "<p><strong>Дано:</strong></p><p>Масса первого груза: $M_1$</p><p>Масса второго груза: $M_2$</p><p>Максимальная сила натяжения, которую выдерживает шнур: $T$</p><p>Коэффициент трения между грузами и поверхностью: $\mu$</p><p>Ускорение свободного падения: $g$</p><p><strong>Найти:</strong></p><p>Условие для силы $F$, при котором шнур не разорвется.</p><p><strong>Решение:</strong></p><p>Рассмотрим силы, действующие на грузы. На каждый груз действует сила тяжести, сила нормальной реакции опоры и сила трения. Сила трения скольжения (или максимальная сила трения покоя) для первого груза равна $F_{тр1} = \mu N_1 = \mu M_1 g$, а для второго $F_{тр2} = \mu N_2 = \mu M_2 g$.</p><p>Чтобы система пришла в движение, приложенная сила $F$ должна как минимум преодолеть силу трения покоя первого груза, то есть $F &gt; F_{тр1} = \mu M_1 g$. При этом шнур натянется. Обозначим силу натяжения шнура как $T'$. Шнур не разорвется, пока $T' \le T$.</p><p>Возможны два принципиально разных случая, в зависимости от прочности шнура $T$ и силы трения второго груза $F_{тр2}$.</p><p><strong>1.</strong> Случай, когда шнур "недостаточно прочный": $T \le \mu M_2 g$</p><p>В этом случае максимальная сила натяжения, которую выдерживает шнур ($T$), меньше или равна силе, необходимой для того, чтобы сдвинуть с места второй груз ($\mu M_2 g$). Это означает, что шнур порвется еще до того, как второй груз начнет движение. Разрыв произойдет в тот момент, когда сила натяжения $T'$ достигнет своего предельного значения $T$. В этот момент на первый груз действуют: приложенная сила $F$, сила натяжения $T$ (направлена против $F$) и сила трения $F_{тр1}$ (также против $F$).</p><p>Поскольку второй груз не движется, ускорение первого груза в момент разрыва можно считать равным нулю (предельный случай, когда груз вот-вот начнет ускоряться или движется равномерно). Тогда по первому закону Ньютона для первого груза:</p><p>$F_{max} - T - F_{тр1} = 0$</p><p>$F_{max} = T + F_{тр1} = T + \mu M_1 g$</p><p>Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:</p><p>$F &lt; T + \mu M_1 g$</p><p><strong>2.</strong> Случай, когда шнур "достаточно прочный": $T &gt; \mu M_2 g$</p><p>В этом случае шнур способен выдержать натяжение, необходимое для преодоления силы трения второго груза. Значит, при достаточно большой силе $F$ оба груза будут двигаться с одинаковым ускорением $a$.</p><p>Запишем второй закон Ньютона для каждого груза в проекции на горизонтальную ось:</p><p>Для второго груза ($M_2$): $T' - F_{тр2} = M_2 a \implies T' - \mu M_2 g = M_2 a$</p><p>Для первого груза ($M_1$): $F - T' - F_{тр1} = M_1 a \implies F - T' - \mu M_1 g = M_1 a$</p><p>Шнур разорвется, когда сила натяжения $T'$ достигнет максимального значения $T$. Найдем максимальное ускорение $a_{max}$, при котором это произойдет, из уравнения для второго груза:</p><p>$T - \mu M_2 g = M_2 a_{max} \implies a_{max} = \frac{T - \mu M_2 g}{M_2}$</p><p>Теперь найдем максимальную силу $F_{max}$, которая создает это ускорение. Проще всего рассмотреть систему из двух грузов как единое целое с массой $(M_1 + M_2)$.</p><p>$F_{max} - F_{тр1} - F_{тр2} = (M_1 + M_2)a_{max}$</p><p>$F_{max} - \mu M_1 g - \mu M_2 g = (M_1 + M_2)a_{max}$</p><p>$F_{max} = \mu(M_1 + M_2)g + (M_1 + M_2)a_{max}$</p><p>Подставим выражение для $a_{max}$:</p><p>$F_{max} = (M_1 + M_2)(\mu g + a_{max}) = (M_1 + M_2)\left(\mu g + \frac{T - \mu M_2 g}{M_2}\right)$</p><p>Приведем к общему знаменателю выражение в скобках:</p><p>$F_{max} = (M_1 + M_2)\left(\frac{\mu g M_2 + T - \mu M_2 g}{M_2}\right) = (M_1 + M_2)\frac{T}{M_2}$</p><p>$F_{max} = T\left(\frac{M_1 + M_2}{M_2}\right) = T\left(1 + \frac{M_1}{M_2}\right)$</p><p>Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:</p><p>$F &lt; T\left(1 + \frac{M_1}{M_2}\right)$</p><p><strong>Ответ:</strong></p><p>Чтобы шнур не разорвался, приложенная сила $F$ должна удовлетворять одному из двух условий в зависимости от прочности шнура:</p><p><strong>1.</strong> Если $T \le \mu M_2 g$, то $F &lt; T + \mu M_1 g$.</p><p><strong>2.</strong> Если $T &gt; \mu M_2 g$, то $F &lt; T\left(1 + \frac{M_1}{M_2}\right)$.</p>"
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                  #connection: "mysql"
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                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
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                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_author" => Illuminate\Database\Eloquent\Collection {#1294
              #items: array:3 [
                0 => App\Models\Term {#1295
                  #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 [ …12]
                  #original: array:12 [ …12]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                1 => App\Models\Term {#1297
                  #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 [ …12]
                  #original: array:12 [ …12]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                2 => App\Models\Term {#1298
                  #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 [ …12]
                  #original: array:12 [ …12]
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1299
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1300
              #items: array:1 [
                0 => App\Models\Term {#1301
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
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                  #escapeWhenCastingToString: false
                  #attributes: array:10 [ …10]
                  #original: array:10 [ …10]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_country" => Illuminate\Database\Eloquent\Collection {#1302
              #items: array:1 [
                0 => App\Models\Term {#1303
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_city" => Illuminate\Database\Eloquent\Collection {#1304
              #items: array:1 [
                0 => App\Models\Term {#1305
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_series" => Illuminate\Database\Eloquent\Collection {#1306
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1307
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1308
              #items: array:1 [
                0 => App\Models\Term {#1309
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
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                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #touches: []
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1310
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_publication_number" => null
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1311
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1312
              #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
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            "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 {#1313
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_new_book" => Illuminate\Database\Eloquent\Collection {#1314
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_old_book" => Illuminate\Database\Eloquent\Collection {#1315
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1316
              #items: array:1 [
                0 => App\Models\Term {#1317
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #dateFormat: null
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                  #touches: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_metatags_title" => null
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            "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"
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            "field_subject" => Illuminate\Database\Eloquent\Collection {#1270}
            "field_class" => Illuminate\Database\Eloquent\Collection {#1278}
            "field_publisher" => Illuminate\Database\Eloquent\Collection {#1275}
            "field_author" => Illuminate\Database\Eloquent\Collection {#1294}
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1299}
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1300}
            "field_country" => Illuminate\Database\Eloquent\Collection {#1302}
            "field_city" => Illuminate\Database\Eloquent\Collection {#1304}
            "field_series" => Illuminate\Database\Eloquent\Collection {#1306}
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1307}
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1308}
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1310}
            "field_publication_number" => null
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1311}
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1312}
            "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 {#1313}
            "field_new_book" => Illuminate\Database\Eloquent\Collection {#1314}
            "field_old_book" => Illuminate\Database\Eloquent\Collection {#1315}
            "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1316}
            "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
            ]
          ]
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            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "page" => Illuminate\Database\Eloquent\Collection {#1325
      #items: array:1 [
        0 => App\Models\BookPage {#1324
          #connection: "mysql"
          #table: "book_pages"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
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          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:21 [
            "id" => 1341006
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "45"
            "field_url" => "/10-klass/fizika/gelfgat-zadachnik/page-45"
            "field_display_title" => "45"
            "field_folder" => "1"
            "field_image_name" => "45"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1326
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1327
              #items: array:1 [
                0 => App\Models\Book {#1276}
              ]
              #escapeWhenCastingToString: false
            }
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "edition_groups" => Illuminate\Database\Eloquent\Collection {#1328
              #items: []
              #escapeWhenCastingToString: false
            }
            "content" => Illuminate\Database\Eloquent\Collection {#1338
              #items: array:1 [
                0 => App\Models\Element {#1337
                  #connection: "mysql"
                  #table: "elements"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "next" => array:2 [
              "refs" => "1341007"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "1341005"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1745
              #items: array:3 [
                0 => App\Models\Task {#1755
                  #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 [ …24]
                  #original: array:24 [ …24]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #dispatchesEvents: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                1 => App\Models\Task {#1762
                  #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 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                2 => App\Models\Task {#1774
                  #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 [ …24]
                  #original: array:24 [ …24]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:21 [
            "id" => 1341006
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "45"
            "field_url" => "/10-klass/fizika/gelfgat-zadachnik/page-45"
            "field_display_title" => "45"
            "field_folder" => "1"
            "field_image_name" => "45"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1326}
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1327}
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "edition_groups" => Illuminate\Database\Eloquent\Collection {#1328}
            "content" => Illuminate\Database\Eloquent\Collection {#1338}
            "next" => array:2 [
              "refs" => "1341007"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "1341005"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1745}
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
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          #touches: []
          +timestamps: true
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          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
  ]
  #original: array:24 [
    "id" => 1319454
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "45"
    "field_page_end" => null
    "field_url" => "/10-klass/fizika/gelfgat-zadachnik/06-5"
    "field_display_title" => "6.5"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037}
    "field_metatags_title" => null
    "field_metatags_description" => null
    "field_h1" => null
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    "field_description_bottom" => null
    "field_match" => null
    "breadcrumbs" => []
    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035}
    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1074}
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1268}
    "content" => Illuminate\Database\Eloquent\Collection {#1269}
    "next" => array:2 [
      "refs" => "1319455"
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    ]
    "previous" => array:2 [
      "refs" => "1319453"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1320}
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№6.5 (с. 45)
Условие. №6.5 (с. 45)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 45, номер 6.5, Условие

6.5. Два груза массами $M_1$ и $M_2$, связанные шнуром, лежат на горизонтальной поверхности. Шнур выдерживает силу натяжения $\text{T}$. Коэффициент трения между каждым из грузов и поверхностью равен $\mu$. С какой постоянной силой $\text{F}$ можно тянуть первый груз параллельно шнуру, чтобы шнур не разорвался?

$F < T + \mu M_1 g$ при $T < \mu M_2 g$; $F < T(1 + M_1/M_2)$ при $T > \mu M_2 g$.

Решение. Если сила $\text{F}$ совсем мала, шнур даже не натянется: чтобы он натянулся, надо сначала сдвинуть с места первый груз, а это произойдет только при $F > \mu M_1 g$. Что будет при дальнейшем увеличении $\text{F}$? Если шнур недостаточно прочный $(T < \mu M_2 g)$, то он порвется еще до того, как сдвинется с места второй груз, при $F_{max} = T + \mu M_1 g$. Если же шнур достаточно прочный, то силу $\text{F}$ можно увеличивать без опасности разрыва шнура до тех пор, пока ускорение системы не достигнет максимального значения

$a_{max} = \frac{T - \mu M_2 g}{M_2}$.

При этом $F_{max} = (M_1 + M_2)(a_{max} + \mu g) = T(1 + \frac{M_1}{M_2})$.

Решение. №6.5 (с. 45)

Дано:

Масса первого груза: $M_1$

Масса второго груза: $M_2$

Максимальная сила натяжения, которую выдерживает шнур: $T$

Коэффициент трения между грузами и поверхностью: $\mu$

Ускорение свободного падения: $g$

Найти:

Условие для силы $F$, при котором шнур не разорвется.

Решение:

Рассмотрим силы, действующие на грузы. На каждый груз действует сила тяжести, сила нормальной реакции опоры и сила трения. Сила трения скольжения (или максимальная сила трения покоя) для первого груза равна $F_{тр1} = \mu N_1 = \mu M_1 g$, а для второго $F_{тр2} = \mu N_2 = \mu M_2 g$.

Чтобы система пришла в движение, приложенная сила $F$ должна как минимум преодолеть силу трения покоя первого груза, то есть $F > F_{тр1} = \mu M_1 g$. При этом шнур натянется. Обозначим силу натяжения шнура как $T'$. Шнур не разорвется, пока $T' \le T$.

Возможны два принципиально разных случая, в зависимости от прочности шнура $T$ и силы трения второго груза $F_{тр2}$.

1. Случай, когда шнур "недостаточно прочный": $T \le \mu M_2 g$

В этом случае максимальная сила натяжения, которую выдерживает шнур ($T$), меньше или равна силе, необходимой для того, чтобы сдвинуть с места второй груз ($\mu M_2 g$). Это означает, что шнур порвется еще до того, как второй груз начнет движение. Разрыв произойдет в тот момент, когда сила натяжения $T'$ достигнет своего предельного значения $T$. В этот момент на первый груз действуют: приложенная сила $F$, сила натяжения $T$ (направлена против $F$) и сила трения $F_{тр1}$ (также против $F$).

Поскольку второй груз не движется, ускорение первого груза в момент разрыва можно считать равным нулю (предельный случай, когда груз вот-вот начнет ускоряться или движется равномерно). Тогда по первому закону Ньютона для первого груза:

$F_{max} - T - F_{тр1} = 0$

$F_{max} = T + F_{тр1} = T + \mu M_1 g$

Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:

$F < T + \mu M_1 g$

2. Случай, когда шнур "достаточно прочный": $T > \mu M_2 g$

В этом случае шнур способен выдержать натяжение, необходимое для преодоления силы трения второго груза. Значит, при достаточно большой силе $F$ оба груза будут двигаться с одинаковым ускорением $a$.

Запишем второй закон Ньютона для каждого груза в проекции на горизонтальную ось:

Для второго груза ($M_2$): $T' - F_{тр2} = M_2 a \implies T' - \mu M_2 g = M_2 a$

Для первого груза ($M_1$): $F - T' - F_{тр1} = M_1 a \implies F - T' - \mu M_1 g = M_1 a$

Шнур разорвется, когда сила натяжения $T'$ достигнет максимального значения $T$. Найдем максимальное ускорение $a_{max}$, при котором это произойдет, из уравнения для второго груза:

$T - \mu M_2 g = M_2 a_{max} \implies a_{max} = \frac{T - \mu M_2 g}{M_2}$

Теперь найдем максимальную силу $F_{max}$, которая создает это ускорение. Проще всего рассмотреть систему из двух грузов как единое целое с массой $(M_1 + M_2)$.

$F_{max} - F_{тр1} - F_{тр2} = (M_1 + M_2)a_{max}$

$F_{max} - \mu M_1 g - \mu M_2 g = (M_1 + M_2)a_{max}$

$F_{max} = \mu(M_1 + M_2)g + (M_1 + M_2)a_{max}$

Подставим выражение для $a_{max}$:

$F_{max} = (M_1 + M_2)(\mu g + a_{max}) = (M_1 + M_2)\left(\mu g + \frac{T - \mu M_2 g}{M_2}\right)$

Приведем к общему знаменателю выражение в скобках:

$F_{max} = (M_1 + M_2)\left(\frac{\mu g M_2 + T - \mu M_2 g}{M_2}\right) = (M_1 + M_2)\frac{T}{M_2}$

$F_{max} = T\left(\frac{M_1 + M_2}{M_2}\right) = T\left(1 + \frac{M_1}{M_2}\right)$

Чтобы шнур не разорвался, приложенная сила должна быть строго меньше этого значения:

$F < T\left(1 + \frac{M_1}{M_2}\right)$

Ответ:

Чтобы шнур не разорвался, приложенная сила $F$ должна удовлетворять одному из двух условий в зависимости от прочности шнура:

1. Если $T \le \mu M_2 g$, то $F < T + \mu M_1 g$.

2. Если $T > \mu M_2 g$, то $F < T\left(1 + \frac{M_1}{M_2}\right)$.

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