Question

In 2 minutes, a ski lift raises four skiers at a constant speed to a height of 123 m. The average mass of each skier is 71 kg. What is the average power provided by the tension in the cable pulling the lift

Answer 1

Answer:

The average power  provided by the tension in the cable pulling the lift is = 714 W

Explanation:

Given data

Mass = 71 kg

Change in height = 123 m

When the lift moves in upward direction then in that case kinetic energy is constant & only potential energy changes.

Change in potential energy Δ PE = m g ( $h_f - h _ i$ )

Δ PE = 71 × 9.81 × 123

Δ PE = 85670.73 J

Time = 2 min = 120 sec

So average power is given by

$P_{avg} = \frac{Change \ in \ potential \ energy}{Time}$

$P_{avg} = \frac{85670.73}{120}$

$P_{avg} = 714 \ W$

Therefore the average power  provided by the tension in the cable pulling the lift is = 714 W