A man of mass 50kg ascends a flight of stains 5m high in 5 seconds. If acceleration due to gravity is 10ms\(^{-2}\) the power expended is
- 100w
- 200w
- 400w
-
500w
The correct answer is: D
Explanation
Power is the time rate of doing worki.e power = \(\frac{\text{energy}}{\text{time}}\)
Since energy = mgH
∴ power = \(\frac{mgH}{t}\)
= \(\frac{50 \times 10 \times 5}{t}\)
= 500W
There is an explanation video available .