Question

What is the power of a pump which takes 10
seconds to lift 100 kg of water to a water tank situated at a height of
20 m? (8 = 10 m s-2)​

Answer 1

Given:

• Height, h = 20 m

• Mass of water, m = 100 kg

• Acceleration due to gravity, g = 10 m/s²

• Time taken, t = 10 sec

To be calculated:

Calculate the Power?

Formula used:

• W = m × g × h

• P = W/t

Solution:

First of all, we have to calculate the work done by pump in lifting the water against the force of gravity.

Work done = m × g × h

★ Substituting the values in the above formula,we get

Work done = 100 × 10 × 20

= 1000 × 20

= 20000 J

Now,

We know that:

Power = W / t

= 20000 / 10

= 2000 watts

Thus, the power of pump is 2000 watts.

Answer 2

Explanation :

Time taken by pump to lift 100 kg of water to a height of 20 m is 10 seconds. Gravitational acceleration = 10 ms-²

What is power of pump?

Now we have to find work done by pump to lift it at that height at first.

We know,

Work done (w) = m × g × h

⇒ W = 100 × 10 × 20

⇒ W = 1000 × 20

⇒ W = 20000 J

∴ Work done by pump = 20000 Joules.

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Now we know,

Power (P) = Work done / Time

⇒ P = 20000/10

⇒ P = 2000

⇒ P = 2000 W

∴ Power of pump = 2000 Watts.