Предмет: Физика, автор: ksusha1413

Ящик с гвоздями, масса которого 54 кг, поднимают на подвижном блоке, действуя на веревку с силой, модуль которого 300 Н. Определите силу трения и КПД механизма? Весом блока пренебречь.

Ответы

Автор ответа: valeria575

Если бы трение равнялось нулю, то, что бы поднять ящик потребовалась бы сила F = m*g/2 = 540/2 = 270 Ньютонов. Но приложена сила = 300 Н. Значит, сила трения Fтр = 300-270 = 30 Н. И КПД = 270/300 = 0,9

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