A 2 kg block is attached to a spring with a spring constant of 200 N m⁻¹. The block is pulled 0.1 m to compress the spring and then released. Describe the energy changes that take place from the moment the block is held in the compressed position until it comes to rest after the first oscillation.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
The spring stores elastic potential energy when compressed.
When released, the stored elastic potential energy is converted into kinetic energy of the block at the equilibrium position.
The kinetic energy is then converted back into elastic potential energy on the opposite side of the equilibrium, reaching the same maximum value.
Energy losses due to friction/air resistance dissipate the mechanical energy as heat, so the block comes to rest after the first oscillation.
When released, the stored elastic potential energy is converted into kinetic energy of the block at the equilibrium position.
The kinetic energy is then converted back into elastic potential energy on the opposite side of the equilibrium, reaching the same maximum value.
Energy losses due to friction/air resistance dissipate the mechanical energy as heat, so the block comes to rest after the first oscillation.
Examiner tips
- Use the exact terms ‘elastic potential energy’, ‘kinetic energy’, ‘friction/air resistance’. Show the sequence: compression → potential → kinetic → potential → loss. Keep each point brief to match the 4‑mark structure.
Common mistakes
- Mixing up the order of energy conversion. Forgetting to mention the energy loss to heat. Using vague terms like ‘energy’ instead of specifying the type.
Mark scheme (4 marks)
- The spring stores elastic potential energy when compressed.
- When released, the stored elastic potential energy is converted into kinetic energy of the block at the equilibrium position.
- The kinetic energy is then converted back into elastic potential energy on the opposite side of the equilibrium, reaching the same maximum value.
- Energy losses due to friction/air resistance dissipate the mechanical energy as heat, so the block comes to rest after the first oscillation.
Related
- All AQA GCSE Physics (8463) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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