9th Class
Science
Work and energy
Question Bank
Work, Energy and Power
question_answer
A crane is used to lift 1000 kg of coal from a mine 100 m deep. If the time taken by the crane is 1 hr then find the power of the crane, assuming the efficiency of the crane to be 80%. \[\left( \text{g }=\text{9}.\text{8 m}/{{\text{s}}^{\text{2}}} \right)\]