Physics problems ........?

Question

A 20kg object was dragged along a 5 meter distance.The force exerted was 50 N
a.how much work is done?
b.how much work is needed to lift the object 5 m.?
c.compare the work done in both cases.

Answer 1

Work = force*distance acted over = 50N * 5 m = 250 N-m

Lifting the object requires moving an upward force of F = m g = 20 kg * 9.8 m/s^2 = 196 Nts. So the work is

Work = 196 * 5 Nt-m = 980 Nt-m

Work in lifting the object is greater because the force of gravity is greater than the force of friction when dragging the object along the ground.