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BECE Science 2021 Paper

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Question : 28

Total: 40

A machine lifts a load of 100 N through a vertical distance of 2 m in 10s.

What is the power of the machine?

50 W
20 W
10 W
2 W

Solution:

Concept:

Power is the rate of doing work, given by

\text{Power} = \frac{\text{Work Done}}{\text{Time}}

.

Explanation:

Work done is calculated as

\text{Work} = \text{Force} \times \text{Distance}

.

Here, Force

= 100\ \text{N}

and Distance

= 2\ \text{m}

.

So, Work Done

= 100 \times 2 = 200\ \text{J}

.

Time taken

= 10\ \text{s}

.

Therefore, Power

= \frac{200\ \text{J}}{10\ \text{s}} = 20\ \text{W}

.

Answer:

20\ \text{W}

(Option B).

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