Answer to Question #257303 in Mechanics | Relativity for Anonymous005

Question

A weight lifter slowly lifts a 100 kg mass from the floor up a vertical distance of 1.90 m and then slowly lets it down to the floor again.

1. Find the work done by the weight of the mass on the way up.
2. Find the work done by the force exerted by the weight lifter when lifting the weight up.
3. What is the total work done by the weight on the way up and the way down?

Answer 1

1)

$A_1=mgh=1860~J,$

2)

$A_2=mg(h-h)=0~J,$

3)

$A_3=2mgh=3720~J.$