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PART - 1 CH - 5Work, Energy and Power — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsPART - 1 CH - 5Work, Energy and Power2 Marks
Question
A pump engine pulls 100 kg of water to a height of 10 m in 10 seconds, while the efficiency of the engine is $6 0$ percent. What will be the actual power of the engine ( $g =10 m / s ^2$ )?
✓

Answer

It is given, $M=100 kg$
$\begin{aligned}
g & =10 m / s^2 \\
h & =10 m \\
t & =10 seconds
\end{aligned}$
Power of pump engine
$\begin{array}{l}
=\frac{m g h}{t} \\
=\frac{100 \times 10 \times 10}{10}=1000 watt \\
=1 kw
\end{array}$
Let the actual power of engine $=x kw$
$\begin{aligned}
\frac{x \times 60}{100} & =1 kw \\
\Rightarrow \quad x & =\frac{100 \times 1}{60} kw \\
& =1.67 kw \quad Ans.
\end{aligned}$

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