Question

A boy pushes a rock up a hill in 20 seconds. If he applied a force of 20 N over a distance of 5 m on the rock, calculate the power required in this situation.

80 watts
0.2 watts
2,000 watts
5 watts

Answer 1

Here is your answer

`<b>5 watts</b>`

REASON :

Given,

t= 20 secs

F= 20 N

s (displacement)= 5m

Now,

Power= \frac{Work done}{time}

P= W/t ...... (i)

W= F×s×cos(theta)

W= 20×5 × 1 (theta is 0 degree; so cos0= 1)

W= 100 J

Hence,

P= 100/20 (from eq. i)

P= 5 watts

HOPE IT IS USEFUL