A crane lifts a crate of mass 80 kg vertically upwards at a constant speed of 2.5 m s-1, as shown in the diagram below. The electric motor driving the crane operates with an efficiency of 70%.
Taking the acceleration due to gravity as g=9.8 m s−2g = 9.8\text{ m s}^{-2}g=9.8 m s−2, find the input electrical power of the motor.
1.37 kW1.37\text{ kW}1.37 kW
1.96 kW1.96\text{ kW}1.96 kW
2.80 kW2.80\text{ kW}2.80 kW
0.286 kW0.286\text{ kW}0.286 kW