An athlete decides to measure their personal power rating by climbing a vertical ladder.
State the three physical quantities that must be measured in order to calculate the athlete's average power output during the climb, and name a suitable measuring instrument for each quantity.
One climber is measured as having a power output of 450 W450\text{ W}450 W. Their weight is 750 N750\text{ N}750 N.
They climb a vertical ladder whose rungs are spaced 20 cm20\text{ cm}20 cm apart.
How many rungs can they climb in 6 s6\text{ s}6 s?
The human body is only about 12%12\%12% efficient when climbing ladders.
Calculate the actual energy used by the climber's body when they climb 242424 rungs.
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.