A dolphin has a mass of 120 kg120\text{ kg}120 kg.
The dolphin leaps vertically out of the water, leaving the surface with a kinetic energy of 2160 J2160\text{ J}2160 J.
Calculate the speed of the dolphin as it leaves the water.
Calculate the maximum height gained by the dolphin. Ignore air resistance. (Take g=9.8 m/s2g = 9.8\text{ m/s}^2g=9.8 m/s2 or 10 m/s210\text{ m/s}^210 m/s2).
After the dolphin has re-entered the water, it eventually comes to rest and has lost nearly all its original kinetic energy. State what has happened to this lost energy.
Another dolphin, of much greater mass, leaves the water vertically with the same initial speed.
State and explain how the maximum height of this dolphin's jump compares to the height reached by the first dolphin.
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.