An electric motor is used to lift a metal block vertically from the ground to a high shelf. The block is then returned to the ground, and a second motor is used to lift the same block back up to the same shelf.
Which statement must be correct?
The second motor does the same work on the block as the first motor.
The second motor takes the same time to lift the block as the first motor.
The second motor develops the same power as the first motor.
The second motor takes the same time and develops the same power as the first motor.
533 exam-style questions on CIE IGCSE Physics 1.7 Energy, work and power, covering 1.7.1a Energy stores and energy transfers, 1.7.1b Conservation of energy, 1.7.1c Kinetic and gravitational potential energy, 1.7.2 Work done, 1.7.3 Energy resources, 1.7.3a Energy resources and electricity generation, 1.7.3b Nuclear fusion as an energy source, 1.7.3c Efficiency of energy transfer, and 1.7.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.