A-level · Work, energy & power

Kinetic and potential energyExam-style questions

Kinetic energy ½mv² and gravitational potential energy mgh, the work–energy principle (the work done by the resultant force equals the change in kinetic energy), and conservation of mechanical energy — including motion along a smooth curved path, where only the overall energy change matters.

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15 questions · A Level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 1Level 3Level 4Level 5
  1. 1
    A particle of mass 2 kg2\text{ kg} starts from rest on a smooth horizontal surface. A constant horizontal force of 6 N6\text{ N} acts on it over a distance of 6 m6\text{ m}. Using the work–energy principle, find the speed of the particle after it has moved 6 m6\text{ m}. (4 marks)
    Level 3 · 4 marksTry it
  2. 2
    A stone of mass 0.2 kg0.2\text{ kg} is released from rest and falls freely (no air resistance) through a vertical distance of 5 m5\text{ m}. Taking g=10 m s−2g = 10\text{ m s}^{-2}, use conservation of energy to find its speed just before it lands. (4 marks)
    Level 3 · 4 marksTry it
  3. 3
    A particle of mass 3 kg3\text{ kg} accelerates from 4 m s−14\text{ m s}^{-1} to 9 m s−19\text{ m s}^{-1}.

    Find the increase in its kinetic energy. (3 marks)
    Level 3 · 3 marksTry it
  4. 4
    A ball is released from rest at height hh above the ground and falls freely. It reaches the ground moving at 8 m s−18\text{ m s}^{-1}. Take g=10 m s−2g = 10\text{ m s}^{-2}.

    Use energy conservation to find hh. (3 marks)
    Level 3 · 3 marksTry it
  5. 5
    A car of mass 1200 kg1200\text{ kg} travels at 20 m s−120\text{ m s}^{-1}, and a lorry of mass 4800 kg4800\text{ kg} travels at 10 m s−110\text{ m s}^{-1}.
    (a) Find the kinetic energy of each vehicle. (3 marks)
    (b) Comment on your answers. (1 mark)
    Level 3 · 4 marksTry it