Question

A weight lifter lifts a 280-N set of weights from ground level to a position over his head, a vertical distance of 1.60 m. How much work does the weight lifter do, assuming he moves the weights at constant speed?

Answer 1

Given :

A weight lifter lifts a 280-N set of weights from ground level to a position over his head, a vertical distance of 1.60 m.

To Find :

How much work does the weight lifter do, assuming he moves the weights at constant speed.

Solution :

We know, work done is given by :

`W= Fdcos\ \theta`

Here, F = 280 N and d = 1.60 m

Since, weight lifer is applying and upward force and displacement is also in upward direction.

`\theta = 0^(\circ)\\cos\ 0^(\circ) = 1`

Putting all these in above equation, we get :

`W = 280* 1.6* 1\\\\W = 448\ J`

Therefore, work done by weight lifter 448 J.

Hence, this is the required solution.