An electric motor is used to lift a mass of 180 g.
The current in the motor is 1.8 A and the voltage across it is 9.0 V. The motor takes 2.5 s to lift the mass.
Calculate the electrical energy transferred to the motor as it lifts the mass. Give your answer to two significant figures.
State the equation linking gravitational potential energy (GPE), mass, ggg, and height.
The motor lifts the 180 g mass to a height of 75 cm. Calculate the gravitational potential energy gained by the mass. (Use g=9.8 N/kgg = 9.8\text{ N/kg}g=9.8 N/kg or 10 N/kg). Give your answer to two significant figures.
Suggest two reasons why the gravitational potential energy gained by the mass is less than the electrical energy transferred to the motor.
