A pendulum swings in air. Each swing is a little lower than the one before.
Which statement about the total energy of the pendulum and the air together is correct?
The total decreases, because energy is dissipated to the surrounding air
The total stays the same, and the thermal store of the air increases
The total stays the same, and the kinetic store of the pendulum increases
The total decreases, because gravity removes energy from the pendulum
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.