What is the minimum force required to pull the body up the plane?

A body of mass 7.5 kg is to be pulled up along a plane which is inclined at 30o to the horizontal. If the efficiency of the plane is 75%, what is the minimum force required to pull the body up the plane?
(g = 10ms-1)

A. 5.0 N
B. 20.0 N
C. 50.0 N
D. 75.0 N
E. 200.0 N

Correct Answer:

Option C – 50.0 N