JAMB - Physics (2017 - No. 22)
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
Explicació
Power is the time rate of doing work
i.e power = \(\frac{\text{energy}}{\text{time}}\)
Since energy = mgH
∴ power = \(\frac{mgH}{t}\)
= \(\frac{50 \times 10 \times 5}{t}\)
= 500W
i.e power = \(\frac{\text{energy}}{\text{time}}\)
Since energy = mgH
∴ power = \(\frac{mgH}{t}\)
= \(\frac{50 \times 10 \times 5}{t}\)
= 500W