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JAMB Physics 2017 Paper

Question : 22

Total: 49

^{-2}

the power expended is

Solution:

Concept:

Power is the rate of doing work, or energy transferred per second.

Explanation:

The work done against gravity equals the gravitational potential energy gained.

Potential energy gained

= mgh

Here,

m = 50\,kg

g = 10\,ms^{-2}

, and

h = 5\,m

So energy

= 50 \times 10 \times 5 = 2500\,J

Power

= \frac{\text{energy}}{\text{time}} = \frac{mgh}{t}

P = \frac{2500}{5} = 500\,W

Answer:

The power expended is

500\,W

, which is option D.

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