Question

An electric pump has 2kw power. How much water will the pump lift every minute to a height of 10m?

Answer 1

Hint: This is a straight question where the formula of power can be used. After that use the explicit formula of energy. As we know that power is equal to energy per unit time. since height is mentioned in the question, therefore, put the value of energy as mgh. Just used the formula and given data in the question. Put the value in the formula and get the answer.

Complete step by step answer:
Power is defined as energy per unit time.
Mathematically,
$power=\dfrac{energy}{time}$
$\begin{align}
  & power=\dfrac{mgh}{t} \\
 & 2000=\dfrac{m\times 10\times 10}{60} \\
 & m=1200kg \\
\end{align}$
The pump lifts 1200 kg of water.
Additional information:
1 Watt= 1J/s
One minute= 60 second
\[\text{Value of acceleration due to gravity}\left( \text{g} \right)\text{= 9}\text{.8m/}{{\text{s}}^{2}}\]
1K= 1000gram(g)
Density of water= 1000kg/cubic-meter
If you want to convert it into litres then,
$\text{volume=}\dfrac{\text{mass}}{\text{density}}$
\[\text{volume=}\dfrac{1200}{1000}=1.2\text{metercube}\]
1 meter cube= 1000liters

Note: Use the formula of energy which is defined as a product of acceleration due to gravity, mass and height. Assume acceleration due to gravity (g) as 10 which is an approximation of 9.8 to make calculation easy. Generally, when the body is in motion we use kinetic energy and when the body is on some height then we use potential energy. In this question we use potential energy which can be written as only energy. Notice that the body is on some height. You can calculate the volume of water. If you want to convert it into litres then,
$\text{volume=}\dfrac{\text{mass}}{\text{density}}$
\[\text{volume=}\dfrac{1200}{1000}=1.2\text{metercube}\]
1 meter cube= 1000liters
1 Watt= 1J/s
One minute= 60 second
\[\text{Value of acceleration due to gravity}\left( \text{g} \right)\text{= 9}\text{.8m/}{{\text{s}}^{2}}\]
1K= 1000gram(g)
Density of water= 1000kg/cubic-meter