Номер 19.1, страница 140 - 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

Жидкости, пары и твердые тела. 19. Свойства жидкостей. Упражнения - номер 19.1, страница 140.

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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 {#1073}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1107}
          ]
          #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 => "*"
          ]
        }
        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" => 1319329
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "19. Свойства жидкостей"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "140"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
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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 {#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"
                    "updated_at" => null
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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}
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1130 …2}
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                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1132 …2}
                    "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"
                    "field_publication_year" => "2008"
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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]
                    "field_cover_alts" => array:1 [ …1]
                    "field_covers" => array:1 [ …1]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1137 …2}
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                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1140 …2}
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                    "breadcrumbs" => array:3 [ …3]
                  ]
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                    "id" => 5400
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                    "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_under_the_edition_degree" => null
                    "field_cover_description" => "лупа, парень едет на велосипеде"
                    "field_publication_year" => "2008"
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                    "field_part" => ""
                    "field_part_writing" => ""
                    "field_second_foreign_language" => null
                    "field_for_whom" => "Учебное издание"
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                    "field_default_folder" => "/fizika_10/gelfgat-z/"
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                    "field_cover" => array:1 [ …1]
                    "field_cover_alts" => array:1 [ …1]
                    "field_covers" => array:1 [ …1]
                    "field_popular_book" => "0"
                    "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1137 …2}
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                    "breadcrumbs" => array:3 [ …3]
                  ]
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                  #touches: []
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
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              #items: array:1 [
                0 => App\Models\Branch {#1143
                  #connection: "mysql"
                  #table: "branches"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
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                  #perPage: 15
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                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [
                    "id" => 1319328
                    "created_at" => "2026-04-10 13:58:26"
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                    "field_h1" => null
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                    "book" => Illuminate\Database\Eloquent\Collection {#1145 …2}
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                  ]
                  #original: array:24 [
                    "id" => 1319328
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                    "updated_at" => null
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                    "field_branch_order" => null
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1144 …2}
                    "field_page_start" => "140"
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                    "field_branch_covers" => []
                    "book" => Illuminate\Database\Eloquent\Collection {#1145 …2}
                    "branch_parent" => Illuminate\Database\Eloquent\Collection {#1146 …2}
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                  #changes: []
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 1319329
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "19. Свойства жидкостей"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1109}
            "field_page_start" => "140"
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            "field_h1" => null
            "field_description_top" => null
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            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1110}
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          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
          #appends: []
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          #touches: []
          +timestamps: true
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          #hidden: []
          #visible: []
          #fillable: []
          #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" => 1319330
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1148
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "140"
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            "field_h1" => null
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            "field_branch_cover" => []
            "field_branch_covers" => []
            "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
                  +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 {#1151 …2}
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1153 …2}
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1156 …2}
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1158 …2}
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1162 …2}
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1163 …2}
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1165 …2}
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1167 …2}
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                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1171 …2}
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1173 …2}
                    "field_publication_number" => null
                    "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1174 …2}
                    "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1175 …2}
                    "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"
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                    "field_default_folder" => "/fizika_10/gelfgat-z/"
                    "field_isbn" => "978-5-89237-252-7"
                    "field_cover" => array:1 [ …1]
                    "field_cover_alts" => array:1 [ …1]
                    "field_covers" => array:1 [ …1]
                    "field_popular_book" => "0"
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                    "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1179 …2}
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                    "breadcrumbs" => array:3 [ …3]
                  ]
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                    "field_cover" => array:1 [ …1]
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                    "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1179 …2}
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                    "breadcrumbs" => array:3 [ …3]
                  ]
                  #changes: []
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                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1181
              #items: array:1 [
                0 => App\Models\Branch {#1182
                  #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" => 1319329
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
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                    "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1183 …2}
                    "field_page_start" => "140"
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            "text" => "<p><strong>19.1.</strong> Действительно ли нельзя носить воду в решете? Пусть тонкие нити решета протянуты на расстоянии $d = 1,0$ мм друг от друга. Сколько воды можно унести в таком круглом решете радиусом $r = 10$ см? Считайте, что нити водой не смачиваются.</p><p>☑ Около 1 л.</p><p><strong><em>Решение.</em></strong> Вода не будет выливаться из решета, если равнодействующая сил поверхностного натяжения компенсирует силу тяжести. Рассмотрим столб воды, в основании которого — квадратик, образованный нитями решета. При максимально возможной высоте $\text{h}$ слоя воды силы поверхностного натяжения направлены вверх, и их равнодействующая равна $4\sigma d$. Она уравновешивает силу тяжести столба воды $\rho d^2 g h$. Отсюда $h = \frac{4\sigma}{\rho g d} = 3$ см, тогда масса воды $m = \pi r^2 h \rho \approx 1$ (кг).</p>"
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            "text" => "<p><strong>19.1.</strong> Действительно ли нельзя носить воду в решете? Пусть тонкие нити решета протянуты на расстоянии $d = 1,0$ мм друг от друга. Сколько воды можно унести в таком круглом решете радиусом $r = 10$ см? Считайте, что нити водой не смачиваются.</p><p>☑ Около 1 л.</p><p><strong><em>Решение.</em></strong> Вода не будет выливаться из решета, если равнодействующая сил поверхностного натяжения компенсирует силу тяжести. Рассмотрим столб воды, в основании которого — квадратик, образованный нитями решета. При максимально возможной высоте $\text{h}$ слоя воды силы поверхностного натяжения направлены вверх, и их равнодействующая равна $4\sigma d$. Она уравновешивает силу тяжести столба воды $\rho d^2 g h$. Отсюда $h = \frac{4\sigma}{\rho g d} = 3$ см, тогда масса воды $m = \pi r^2 h \rho \approx 1$ (кг).</p>"
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            "text" => "<p><strong>19.1.</strong> Вопреки известной поговорке, воду в решете носить можно, но при определенных условиях. Это возможно благодаря явлению поверхностного натяжения. Вода не будет выливаться из ячеек решета, если сила поверхностного натяжения, действующая по периметру каждой ячейки, будет уравновешивать вес столбика воды в этой ячейке.</p><p><strong>Дано</strong></p><p>Расстояние между нитями (сторона ячейки), $d = 1.0 \text{ мм} = 1.0 \cdot 10^{-3} \text{ м}$<br>Радиус решета, $r = 10 \text{ см} = 0.1 \text{ м}$<br>Плотность воды, $\rho \approx 1000 \text{ кг/м}^3$<br>Коэффициент поверхностного натяжения воды (при 20°C), $\sigma \approx 7.3 \cdot 10^{-2} \text{ Н/м}$<br>Ускорение свободного падения, $g \approx 9.8 \text{ м/с}^2$</p><p><strong>Найти:</strong></p><p>Массу воды $m$, которую можно унести в решете.</p><p><strong>Решение</strong></p><p>Рассмотрим одну квадратную ячейку решета со стороной $d$. Вода не выливается, так как на границе воды с нитями возникает сила поверхностного натяжения. Поскольку нити не смачиваются водой, эта сила направлена вертикально вверх и препятствует вытеканию. Величина этой силы для одной ячейки равна произведению коэффициента поверхностного натяжения $\sigma$ на длину периметра ячейки $L = 4d$.</p><p>$F_{\sigma} = \sigma L = 4\sigma d$</p><p>Эта сила должна уравновесить вес столбика воды высотой $h$ над этой ячейкой. Вес столбика воды (сила тяжести) равен:</p><p>$F_{g} = m_{cell}g = \rho V_{cell} g = \rho (d^2 h) g$</p><p>При максимальной высоте слоя воды $h$ эти силы равны:</p><p>$F_{\sigma} = F_{g}$</p><p>$4\sigma d = \rho d^2 h g$</p><p>Отсюда можем выразить максимальную высоту столба воды, который может удержать решето:</p><p>$h = \frac{4\sigma d}{\rho d^2 g} = \frac{4\sigma}{\rho g d}$</p><p>Подставим числовые значения:</p><p>$h = \frac{4 \cdot 7.3 \cdot 10^{-2} \text{ Н/м}}{1000 \text{ кг/м}^3 \cdot 9.8 \text{ м/с}^2 \cdot 1.0 \cdot 10^{-3} \text{ м}} \approx \frac{0.292}{9.8} \approx 0.0298 \text{ м} \approx 3.0 \text{ см}$</p><p>Теперь, зная максимальную высоту слоя воды, можем найти общий объем и массу воды, которую можно унести в круглом решете радиусом $r$. Объем воды равен произведению площади решета $S$ на высоту $h$.</p><p>$V = S \cdot h = \pi r^2 h$</p><p>$V = \pi \cdot (0.1 \text{ м})^2 \cdot 0.0298 \text{ м} \approx 3.14 \cdot 0.01 \text{ м}^2 \cdot 0.0298 \text{ м} \approx 9.36 \cdot 10^{-4} \text{ м}^3$</p><p>Масса воды находится по формуле $m = \rho V$.</p><p>$m = 1000 \text{ кг/м}^3 \cdot 9.36 \cdot 10^{-4} \text{ м}^3 \approx 0.936 \text{ кг}$</p><p>Эта масса примерно равна 1 кг. Поскольку плотность воды равна 1000 кг/м³ (или 1 кг/л), объем такой массы воды составляет около 1 литра.</p><p><strong>Ответ:</strong> В таком решете можно унести около 0.94 кг воды, что составляет примерно 1 литр.</p>"
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            "text" => "<p><strong>19.1.</strong> Вопреки известной поговорке, воду в решете носить можно, но при определенных условиях. Это возможно благодаря явлению поверхностного натяжения. Вода не будет выливаться из ячеек решета, если сила поверхностного натяжения, действующая по периметру каждой ячейки, будет уравновешивать вес столбика воды в этой ячейке.</p><p><strong>Дано</strong></p><p>Расстояние между нитями (сторона ячейки), $d = 1.0 \text{ мм} = 1.0 \cdot 10^{-3} \text{ м}$<br>Радиус решета, $r = 10 \text{ см} = 0.1 \text{ м}$<br>Плотность воды, $\rho \approx 1000 \text{ кг/м}^3$<br>Коэффициент поверхностного натяжения воды (при 20°C), $\sigma \approx 7.3 \cdot 10^{-2} \text{ Н/м}$<br>Ускорение свободного падения, $g \approx 9.8 \text{ м/с}^2$</p><p><strong>Найти:</strong></p><p>Массу воды $m$, которую можно унести в решете.</p><p><strong>Решение</strong></p><p>Рассмотрим одну квадратную ячейку решета со стороной $d$. Вода не выливается, так как на границе воды с нитями возникает сила поверхностного натяжения. Поскольку нити не смачиваются водой, эта сила направлена вертикально вверх и препятствует вытеканию. Величина этой силы для одной ячейки равна произведению коэффициента поверхностного натяжения $\sigma$ на длину периметра ячейки $L = 4d$.</p><p>$F_{\sigma} = \sigma L = 4\sigma d$</p><p>Эта сила должна уравновесить вес столбика воды высотой $h$ над этой ячейкой. Вес столбика воды (сила тяжести) равен:</p><p>$F_{g} = m_{cell}g = \rho V_{cell} g = \rho (d^2 h) g$</p><p>При максимальной высоте слоя воды $h$ эти силы равны:</p><p>$F_{\sigma} = F_{g}$</p><p>$4\sigma d = \rho d^2 h g$</p><p>Отсюда можем выразить максимальную высоту столба воды, который может удержать решето:</p><p>$h = \frac{4\sigma d}{\rho d^2 g} = \frac{4\sigma}{\rho g d}$</p><p>Подставим числовые значения:</p><p>$h = \frac{4 \cdot 7.3 \cdot 10^{-2} \text{ Н/м}}{1000 \text{ кг/м}^3 \cdot 9.8 \text{ м/с}^2 \cdot 1.0 \cdot 10^{-3} \text{ м}} \approx \frac{0.292}{9.8} \approx 0.0298 \text{ м} \approx 3.0 \text{ см}$</p><p>Теперь, зная максимальную высоту слоя воды, можем найти общий объем и массу воды, которую можно унести в круглом решете радиусом $r$. Объем воды равен произведению площади решета $S$ на высоту $h$.</p><p>$V = S \cdot h = \pi r^2 h$</p><p>$V = \pi \cdot (0.1 \text{ м})^2 \cdot 0.0298 \text{ м} \approx 3.14 \cdot 0.01 \text{ м}^2 \cdot 0.0298 \text{ м} \approx 9.36 \cdot 10^{-4} \text{ м}^3$</p><p>Масса воды находится по формуле $m = \rho V$.</p><p>$m = 1000 \text{ кг/м}^3 \cdot 9.36 \cdot 10^{-4} \text{ м}^3 \approx 0.936 \text{ кг}$</p><p>Эта масса примерно равна 1 кг. Поскольку плотность воды равна 1000 кг/м³ (или 1 кг/л), объем такой массы воды составляет около 1 литра.</p><p><strong>Ответ:</strong> В таком решете можно унести около 0.94 кг воды, что составляет примерно 1 литр.</p>"
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          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "next" => array:2 [
      "refs" => "1319610"
      "type" => "task"
    ]
    "previous" => array:2 [
      "refs" => "1319608"
      "type" => "task"
    ]
    "book" => Illuminate\Database\Eloquent\Collection {#1241
      #items: array:1 [
        0 => App\Models\Book {#1209
          #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"
            "updated_at" => null
            "field_tree_default_status" => "tasks"
            "field_pages_status" => null
            "field_subject" => Illuminate\Database\Eloquent\Collection {#1210
              #items: array:1 [
                0 => App\Models\Term {#1208
                  #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 [ …6]
                    "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 [ …6]
                    "field_foreign_lang_name" => null
                    "field_short_name" => null
                    "field_subject_type" => "technical_subject"
                    "field_translit" => "fizika"
                  ]
                  #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_class" => Illuminate\Database\Eloquent\Collection {#1211
              #items: array:2 [
                0 => App\Models\Term {#1212
                  #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" => 5459
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "10"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "desjatyj"
                  ]
                  #original: array:6 [
                    "id" => 5459
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "10"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "desjatyj"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                1 => App\Models\Term {#1213
                  #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" => 5460
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "11"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "odinadcatyj"
                  ]
                  #original: array:6 [
                    "id" => 5460
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "11"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "odinadcatyj"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_publisher" => Illuminate\Database\Eloquent\Collection {#1214
              #items: array:1 [
                0 => App\Models\Term {#1215
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 5158
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Илекса"
                    "field_cases" => null
                    "field_translit" => "ileksa"
                  ]
                  #original: array:6 [
                    "id" => 5158
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Илекса"
                    "field_cases" => null
                    "field_translit" => "ileksa"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_author" => Illuminate\Database\Eloquent\Collection {#1216
              #items: array:3 [
                0 => App\Models\Term {#1217
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:12 [
                    "id" => 4102
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Гельфгат"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Илья"
                    "field_patronymic" => "Маркович"
                    "field_surname_rp" => null
                  ]
                  #original: array:12 [
                    "id" => 4102
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Гельфгат"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Илья"
                    "field_patronymic" => "Маркович"
                    "field_surname_rp" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                1 => App\Models\Term {#1218
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:12 [
                    "id" => 4104
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Генденштейн"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Лев"
                    "field_patronymic" => "Элевич"
                    "field_surname_rp" => "Генденштейна"
                  ]
                  #original: array:12 [
                    "id" => 4104
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Генденштейн"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Лев"
                    "field_patronymic" => "Элевич"
                    "field_surname_rp" => "Генденштейна"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
                2 => App\Models\Term {#1219
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:12 [
                    "id" => 4583
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Кирик"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Леонид"
                    "field_patronymic" => "Анатольевич"
                    "field_surname_rp" => null
                  ]
                  #original: array:12 [
                    "id" => 4583
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Кирик"
                    "field_bio" => null
                    "field_degree_rp" => null
                    "field_foreign_lang_name" => null
                    "field_foreign_lang_patronymic" => null
                    "field_foreign_lang_surname" => null
                    "field_name" => "Леонид"
                    "field_patronymic" => "Анатольевич"
                    "field_surname_rp" => null
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1220
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1221
              #items: array:1 [
                0 => App\Models\Term {#1222
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:10 [
                    "id" => 6518
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Задачник"
                    "field_book_type_foreign" => null
                    "field_cases" => array:6 [ …6]
                    "field_plural_form" => null
                    "field_short_name" => null
                    "field_short_name_foreign" => null
                    "field_translit" => "zadachnik"
                  ]
                  #original: array:10 [
                    "id" => 6518
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Задачник"
                    "field_book_type_foreign" => null
                    "field_cases" => array:6 [ …6]
                    "field_plural_form" => null
                    "field_short_name" => null
                    "field_short_name_foreign" => null
                    "field_translit" => "zadachnik"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_country" => Illuminate\Database\Eloquent\Collection {#1223
              #items: array:1 [
                0 => App\Models\Term {#1224
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 9
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Россия"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "rossiya"
                  ]
                  #original: array:6 [
                    "id" => 9
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Россия"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "rossiya"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_city" => Illuminate\Database\Eloquent\Collection {#1225
              #items: array:1 [
                0 => App\Models\Term {#1226
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 15
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Москва"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "moskva"
                  ]
                  #original: array:6 [
                    "id" => 15
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "Москва"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "moskva"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_series" => Illuminate\Database\Eloquent\Collection {#1227
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1228
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1229
              #items: array:1 [
                0 => App\Models\Term {#1230
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 40
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "профильный"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "profilnyy"
                  ]
                  #original: array:6 [
                    "id" => 40
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "профильный"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "profilnyy"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1231
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_publication_number" => null
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1232
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1233
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition_degree" => null
            "field_cover_description" => "лупа, парень едет на велосипеде"
            "field_publication_year" => "2008"
            "field_publication_year_until" => null
            "field_part" => ""
            "field_part_writing" => ""
            "field_second_foreign_language" => null
            "field_for_whom" => "Учебное издание"
            "field_allowed" => null
            "field_reserve_field" => null
            "field_link_to_source" => null
            "field_tasks_count" => "459"
            "field_priority" => null
            "field_default_folder" => "/fizika_10/gelfgat-z/"
            "field_isbn" => "978-5-89237-252-7"
            "field_cover" => array:1 [
              0 => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
            ]
            "field_cover_alts" => array:1 [
              0 => ""
            ]
            "field_covers" => array:1 [
              0 => array:4 [
                "path" => "/media/fizika_10/gelfgat-z/covers/cover1.webp?ts=1756049816"
                "alt" => ""
                "width" => "1566"
                "height" => "2412"
              ]
            ]
            "field_popular_book" => "0"
            "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1234
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_new_book" => Illuminate\Database\Eloquent\Collection {#1235
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_old_book" => Illuminate\Database\Eloquent\Collection {#1236
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_url" => "/10-klass/fizika/gelfgat-zadachnik"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1237
              #items: array:1 [
                0 => App\Models\Term {#1238
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [
                    "id" => 46
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "красный"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "krasnyy"
                  ]
                  #original: array:6 [
                    "id" => 46
                    "created_at" => "2026-04-10 13:58:26"
                    "updated_at" => null
                    "name" => "красный"
                    "field_cases" => array:6 [ …6]
                    "field_translit" => "krasnyy"
                  ]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [
                    0 => "*"
                  ]
                }
              ]
              #escapeWhenCastingToString: false
            }
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№19.1 (с. 140)
Условие. №19.1 (с. 140)
скриншот условия
Физика, 10-11 класс Задачник, авторы: Гельфгат Илья Маркович, Генденштейн Лев Элевич, Кирик Леонид Анатольевич, издательство Илекса, Москва, 2008, красного цвета, страница 140, номер 19.1, Условие

19.1. Действительно ли нельзя носить воду в решете? Пусть тонкие нити решета протянуты на расстоянии $d = 1,0$ мм друг от друга. Сколько воды можно унести в таком круглом решете радиусом $r = 10$ см? Считайте, что нити водой не смачиваются.

☑ Около 1 л.

Решение. Вода не будет выливаться из решета, если равнодействующая сил поверхностного натяжения компенсирует силу тяжести. Рассмотрим столб воды, в основании которого — квадратик, образованный нитями решета. При максимально возможной высоте $\text{h}$ слоя воды силы поверхностного натяжения направлены вверх, и их равнодействующая равна $4\sigma d$. Она уравновешивает силу тяжести столба воды $\rho d^2 g h$. Отсюда $h = \frac{4\sigma}{\rho g d} = 3$ см, тогда масса воды $m = \pi r^2 h \rho \approx 1$ (кг).

Решение. №19.1 (с. 140)

19.1. Вопреки известной поговорке, воду в решете носить можно, но при определенных условиях. Это возможно благодаря явлению поверхностного натяжения. Вода не будет выливаться из ячеек решета, если сила поверхностного натяжения, действующая по периметру каждой ячейки, будет уравновешивать вес столбика воды в этой ячейке.

Дано

Расстояние между нитями (сторона ячейки), $d = 1.0 \text{ мм} = 1.0 \cdot 10^{-3} \text{ м}$
Радиус решета, $r = 10 \text{ см} = 0.1 \text{ м}$
Плотность воды, $\rho \approx 1000 \text{ кг/м}^3$
Коэффициент поверхностного натяжения воды (при 20°C), $\sigma \approx 7.3 \cdot 10^{-2} \text{ Н/м}$
Ускорение свободного падения, $g \approx 9.8 \text{ м/с}^2$

Найти:

Массу воды $m$, которую можно унести в решете.

Решение

Рассмотрим одну квадратную ячейку решета со стороной $d$. Вода не выливается, так как на границе воды с нитями возникает сила поверхностного натяжения. Поскольку нити не смачиваются водой, эта сила направлена вертикально вверх и препятствует вытеканию. Величина этой силы для одной ячейки равна произведению коэффициента поверхностного натяжения $\sigma$ на длину периметра ячейки $L = 4d$.

$F_{\sigma} = \sigma L = 4\sigma d$

Эта сила должна уравновесить вес столбика воды высотой $h$ над этой ячейкой. Вес столбика воды (сила тяжести) равен:

$F_{g} = m_{cell}g = \rho V_{cell} g = \rho (d^2 h) g$

При максимальной высоте слоя воды $h$ эти силы равны:

$F_{\sigma} = F_{g}$

$4\sigma d = \rho d^2 h g$

Отсюда можем выразить максимальную высоту столба воды, который может удержать решето:

$h = \frac{4\sigma d}{\rho d^2 g} = \frac{4\sigma}{\rho g d}$

Подставим числовые значения:

$h = \frac{4 \cdot 7.3 \cdot 10^{-2} \text{ Н/м}}{1000 \text{ кг/м}^3 \cdot 9.8 \text{ м/с}^2 \cdot 1.0 \cdot 10^{-3} \text{ м}} \approx \frac{0.292}{9.8} \approx 0.0298 \text{ м} \approx 3.0 \text{ см}$

Теперь, зная максимальную высоту слоя воды, можем найти общий объем и массу воды, которую можно унести в круглом решете радиусом $r$. Объем воды равен произведению площади решета $S$ на высоту $h$.

$V = S \cdot h = \pi r^2 h$

$V = \pi \cdot (0.1 \text{ м})^2 \cdot 0.0298 \text{ м} \approx 3.14 \cdot 0.01 \text{ м}^2 \cdot 0.0298 \text{ м} \approx 9.36 \cdot 10^{-4} \text{ м}^3$

Масса воды находится по формуле $m = \rho V$.

$m = 1000 \text{ кг/м}^3 \cdot 9.36 \cdot 10^{-4} \text{ м}^3 \approx 0.936 \text{ кг}$

Эта масса примерно равна 1 кг. Поскольку плотность воды равна 1000 кг/м³ (или 1 кг/л), объем такой массы воды составляет около 1 литра.

Ответ: В таком решете можно унести около 0.94 кг воды, что составляет примерно 1 литр.

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Мы подготовили для вас ответ c подробным объяснением домашего задания по физике за 10-11 класс, для упражнения номер 19.1 расположенного на странице 140 к задачнику 2008 года издания для учащихся школ и гимназий.

Теперь на нашем сайте ГДЗ.ТОП вы всегда легко и бесплатно найдёте условие с правильным ответом на вопрос «Как решить ДЗ» и «Как сделать» задание по физике к упражнению №19.1 (с. 140), авторов: Гельфгат (Илья Маркович), Генденштейн (Лев Элевич), Кирик (Леонид Анатольевич), профильный уровень обучения учебного пособия издательства Илекса.