Question

A 20N box is pushed 10m up a ramp in 25 seconds. How much power is required?

Answer 1

Given,

The weight of the box, w=20 N

The change in the height of the box, Δh=10 m

The time it takes to push the box up the ramp, t=25 s

Power is the time rate of change of transfer of energy. The power can be calculated as the ratio of the work done to the time it takes to do that work.

Thus the power required to push the box up the ramp is,

`P=(W)/(t)`

Where W is the work done in pushing the box up the ramp.

The work done in pushing the box up the ramp is equal to the gain in the gravitational potential energy by the box and is given by,

`W=w\Delta h`

Thus the power required is,

`P=(w\Delta h)/(t)`

On substituting the known values,

`\begin{gathered} P=(20*10)/(25) \\ =8\text{ W} \end{gathered}`

Thus the power required to push the box up the ramp is 8 W.