Question

мяч, подброшенный вертикально вверх, поднялся на высоту 5м за 1с. Какова средняя мощность силы тяжести за это время, если масса мяча 0,5кг.а)25Втб)50Втв) -25Втг) -50Вт

Answer 1

будет а) т.к.

F=mg

F=0,5кг * 10=5н

A=Fs

A=5н*5м=25дж

N=25дж*1 сек=25 вт

 

Answer 2

The answer is -25 W. Here is a detailed explanation:

The average power of a force is defined as the ratio of the work done by the force to the time interval during which the work is done. The work done by the force of gravity on the ball is equal to the change in the gravitational potential energy of the ball. The gravitational potential energy of the ball is given by the formula:

$$U = mgh$$

where $m$ is the mass of the ball, $g$ is the acceleration due to gravity, and $h$ is the height of the ball above the ground.

The initial height of the ball is zero, and the final height of the ball is 5 m. Therefore, the change in the gravitational potential energy of the ball is:

$$\Delta U = U_f - U_i = mg(h_f - h_i) = 0.5 \times 9.8 \times (5 - 0) = 24.5 J$$

The work done by the force of gravity on the ball is negative, because the force of gravity is opposite to the displacement of the ball. Therefore, the work done by the force of gravity on the ball is:

$$W = -\Delta U = -24.5 J$$

The time interval during which the work is done is 1 s. Therefore, the average power of the force of gravity on the ball is:

$$P = \frac{W}{t} = \frac{-24.5}{1} = -24.5 W$$

To the nearest integer, the answer is -25 W. This means that the force of gravity is doing negative work on the ball, or taking away energy from the ball, at a rate of 25 W.

You can find more information about this topic in the following sources:

- [Упражнение 14 ГДЗ Перышкин 9 класс по физике](https://reshak.ru/otvet/reshebniki.php?otvet=new/Upr/14&predmet=per9) - [Мяч, брошенный вертикально вверх, поднялся на высоту 20 м и упал на землю. Какова средняя мощность силы тяжести за это время, если масса мяча 0,5 кг?](https://tutor.yandex.ru/tutor/subject/problem/?problem_id=T13463)