A container port crane has an efficiency of 64% when hoisting heavy cargo from a container ship.
During a lifting operation lasting 15 s, the gravitational potential energy of a container increases by 2.08 × 106 J.
Calculate the total amount of electrical energy supplied to the crane during this 15 s interval. Use the equation:
efficiency=useful output energy transfertotal input energy transfer \text{efficiency} = \frac{\text{useful output energy transfer}}{\text{total input energy transfer}} efficiency=total input energy transferuseful output energy transfer