Question

A student weighing 700N climbs at constant speed to the top of an 8 m vertical rope in 10s. The average power expended by the student to overcome gravity is most nearly 

(A) 1.1 W 

(B) 87.5 W 

(C) 560 W 

(D) 875 W 

(E) 5,600 W

Answer 1

Correct option (C) 560 W

The student must exert an average force equal to their weight (F_g) in order to lift themselves so the lifting force F=mg. The power is then found with P = Fd/t = (F_g)d/t.