Question

A rock climber wears a 8.1 kg backpack while scaling a cliff. After 28.2 min, the climber is 9.4 m above the starting point. How much work does the climber do on the backpack? If the climber weighs 656 N, how much work does she do lifting herself and the backpack? What is the average power developed by the climber?

Answer 1

Answer:

Explanation:

mass of backpack, m = 8.1 kg

weight of climber, W = 656 N

height raised, h = 9.4 m

time, t = 28.2 min = 28.2 x 60 = 1692 second

weight of backpack, w = m x g = 8.1 x 9.8 = 79.38 N

Work done by the climber on the backpack = mg x h = 79.38 x 9.4 = 746.17 J

Wok done in lifting herself + backpack = (W + w) x h

                                                                 = (656 + 79.38) x 9.4 = 6912.57 J

Power developed by the climber,P = Total work / time

P = 6912.57 / 1692 = 4.09 W