Question 10
Work, Energy and PowerA man whose mass is 80 kg climbs a staircase in 20 s and expends a power of 120 W. Find the height of the staircase. [g = 10 m s−2]
- A.1.8 m
- B.2.0 m
- C.2.5 m
- D.3.0 m
Show the answer and explanation
Answer: D (3.0 m)
Explanation
Work done = power × time = 120 × 20 = 2400 J = mgh, so h = 2400 ÷ (80 × 10) = 3.0 m.