0.25 Hp ની મોટર 600 rpm ની ઝડપથી ભ્રમણ કરે

Motor makes $ 600$ revolution per minute  $n =$ $600\frac{{{\rm{revolution}}}}{{{\rm{minute}}}} = 10\frac{{rev}}{{\sec }}$  

Time required for one revolution $ = \frac{1}{{10}}$sec

Energy required for one revolution = power $×$ time =$\frac{1}{4} \times 746 \times \frac{1}{{10}} = \frac{{746}}{{40}}J$

But work done $= 40\%$  of input $ = 40\% \times \frac{{746}}{{40}} = \frac{{40}}{{100}} \times \frac{{746}}{{40}} = 7.46\,J$