Question

an engine of power 9.8 kW is used to pump water from a mine 40m deep calculate the mass of water it
can pump out in 1 hour ..answer
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Answer 1

Given:

An engine of power 9.8 kW is used to pump water from a mine 40m deep.

To find:

The mass of water that can be pumped out in 1 hour ?

Calculation:

Let the mass of water be "m" :

$\therefore \: power = \dfrac{work}{time}$

$\implies\: power = \dfrac{m \times g \times h}{t}$

$\implies\: 9.8 \times {10}^{3} = \dfrac{m \times 9.8 \times 40}{60 \times 60}$

$\implies\: {10}^{3} = \dfrac{m \times 4}{60 \times 6}$

$\implies\: {10}^{3} = \dfrac{m}{15 \times 6}$

$\implies\: {10}^{3} = \dfrac{m}{90}$

$\implies\: m = 90 \times {10}^{3} \: kg$

$\implies\: m = 9\times {10}^{4} \: kg$

So, mass of water that can be lifted is 9 × 10⁴ kg.