Предмет: Физика, автор: poliesh169

ДАЮ 100 БАЛІВ !!!! На шнурі, перекинутому через нерухомий блок, підвішено вантажі масами 250 та 750 г. Чому дорівнюватиме швидкість вантажів, якщо після початку руху вони пройшли по 5 м? Відповідь запиши у м/с. Відповідь округліть до десятих ​

Ответы

Автор ответа: zinovicgrigorij
1

Ответ: 7м/с

Объяснение:

Дано:

m1=250г=0,25кг

m2=750г=0,75кг

g=10Н/кг

S=5м

-----------------------

V-?

Из третьего закона Ньютона следует, что грузы связаны и движутся с одинаковой скоростью и ускорением.

Сила натяжения нити от первого груза равна:

F1=m1*g-m1*а

Сила натяжения нити от второго груза равна:

F2=m2*g+m2*a

F1=F2

Значит:

m1*g-m1*а=m2*g+m2*a

Преобразуем уравнение и получим:

(m1+m2)*а=(m2-m1)*g

Отсюда:

а=(m2-m1)*g/(m1+m2)=(0,75-0,25)*10/(0,75+0,25)=5м/с²

Путь грузов находим по формуле:

S=Vo*t+at²/2

Vo=0

Значит:

S=at²/2

Отсюда:

t=√(2S/a)=√(2*5/5)=1,4с

V=Vo+at=0*1,4+5*1,4=7м/с

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