A child slides down a playground slide and comes to a stop at the bottom. Describe the energy changes that take place during the slide, including what happens to any waste energy.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
1. Gravitational potential energy of the child decreases as he slides down.
2. The lost potential energy is converted into kinetic energy, making the child move faster.
3. Friction between the child’s clothing and the slide transfers some kinetic energy into thermal energy.
4. The thermal energy (and any sound produced) is waste energy that is dissipated to the surroundings and is not usefully employed.
2. The lost potential energy is converted into kinetic energy, making the child move faster.
3. Friction between the child’s clothing and the slide transfers some kinetic energy into thermal energy.
4. The thermal energy (and any sound produced) is waste energy that is dissipated to the surroundings and is not usefully employed.
Examiner tips
- Use the exact terms: gravitational potential energy, kinetic energy, thermal energy, waste energy.
- Show the energy flow: potential → kinetic → thermal/sound.
- Mention friction as the cause of the energy loss.
- Keep each point brief and to the point.
Common mistakes
- Confusing kinetic energy with potential energy; not recognising friction as the cause of energy loss.
- Omitting the waste energy (thermal/sound) or describing it as useful.
- Using vague terms like ‘energy’ without specifying type.
Mark scheme (4 marks)
- Gravitational potential energy decreases as the child descends
- Gravitational potential energy is transferred to kinetic energy (as the child moves down the slide)
- Friction between the child and the slide causes energy to be transferred to thermal energy stores
- The thermal energy (and any sound energy) is waste energy / dissipated to the surroundings and is not usefully used
Key terms in this question
Related
- All AQA GCSE Physics (8463) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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