A ball of mass 0.050 kg is dropped from a height of 2.0 m onto a hard floor. It bounces back up to a height of 1.4 m.
Gravitational field strength = 10 N/kg
Calculate the energy dissipated between the ball being dropped and reaching the top of its bounce.
Calculate the efficiency of the bounce.
Explain why the ball does not bounce back to its starting height.
Refer to energy stores in your answer.
A student says:
'The energy that the ball loses has been used up.'
Explain why the student is wrong.
50 exam-style questions on OCR GCSE Physics 7.2 Power and efficiency, covering 7.2.1 Dissipation of energy, 7.2.2 Energy transfers in domestic devices, 7.2.3 Power ratings of domestic appliances, 7.2.4 Efficiency of energy transfers, 7.2.5 Ways to increase efficiency, 7.2.6 Reducing unwanted energy transfers, and 7.2.7 Thermal conductivity and the cooling of buildings. Each one has a worked solution and a mark scheme showing where the marks go.