Question

A box is lifted to a height of 6 meters in 3 seconds. If the lift required 400 watts of power, what was the weight of the box?200 N250 N300 N350 N

Answer 1

Given:

The height through which the box was lifted, h=6 m

The time it took to lift the box, t=3 s

The power dissipated in lifting the box, P=400 W

To find:

The weight of the box.

Step-by-step explanation:

The power is described as the time rate of transfer of energy.

Thus the power is given by,

`P=(W)/(t)`

Where W is the work done in lifting the box.

The work done is given by,

`W=F* h`

Where F is the weight of the box.

Thus the power dissipated in lifting the box is given by,

`P=(Fh)/(t)`

On substituting the known values,

`\begin{gathered} 400=(F*6)/(3) \\ \Rightarrow F=(400*3)/(6) \\ =200\text{ N} \end{gathered}`

Final answer:

The weight of the box is 200 N

Thus the correct answer is option A.