A crane takes 15 seconds to lift a heavy crate from the ground to a platform. The useful work done against gravity is WWW. The useful power developed is PPP.
A motorized pulley system takes 10 seconds to lift the same crate from the ground to the same platform.
Which of the following describes the useful work done against gravity and the useful power developed by the pulley system?
Useful work is WWW, useful power is more than PPP
Useful work is WWW, useful power is less than PPP
Useful work is more than WWW, useful power is more than PPP
Useful work is more than WWW, useful power is PPP
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.