Practise O/L exam questions on Energy: Heat, Light and Sound with worked solutions
2019 · Paper II · 5 marks
A 2 kg ball is held at rest 5 m above the ground. (Take g = 10 m/s²)
(i) Calculate the gravitational potential energy of the ball.
(ii) Just before the ball hits the ground (ignoring air resistance), calculate its kinetic energy.
(iii) Name the energy transformation as the ball falls.
Show worked solution
(i) GPE = mgh = 2 × 10 × 5 = 100 J
(ii) By conservation of energy, KE = GPE = 100 J (no energy lost to friction).
(iii) Gravitational potential energy → Kinetic energy.