Предмет: Физика, автор: самира244

при перемещении тела массой 3 кг по горизонтали из состояния покоя с ускорением 2,0 м/сквадрате была совершена работа 96 Дж Сколько времени продолжалось перемещение

ollikahnstex: (Для модераторов) такая задача уже есть решённая: https://znanija.com/task/28731284

Shah55: Самира ты в Узбекистане живешь

Ответы

Автор ответа: ollikahnstex

19

Совершённая работа A равна увеличению кинетической энергии тела Eк:
A = Eк2 - Eк1
Т.к. тело двигалось из состояния покоя, то начальная скорость равна 0, значит и начальная кинетическая энергия Eк1 = 0, тогда:
A = Eк2
A = m*V²/2, где
m – масса тела;
V – конечная скорость тела.

Для равноускоренного движения из состояния покоя конечная скорость V равна:
V = a*t, тогда:
A = m*(a*t)²/2

Отсюда выразим время:
t = √(2*A/(m*a²))
t = √(2 * 96 Дж / (3 кг * (2 м/с²)²))
t = 4 с

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