A boy mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate :
(i)the force of gravity acting the boy .
(ii) the work done by against the force of gravity .
(iii)the power spent by the boy .
(Take g=10 m `S^(-2)`)

Explanation

Let's solve the problem step by step.

### Given:
- Mass of the boy (m) = 40 kg
- Height climbed (h) = 8 m
- Time taken (t) = 5 s
- Acceleration due to gravity (g) = 10 m/s²

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