# A steel car body panel is stamped into shape by a large machine press in a factory. Once the pressing force is removed, the panel keeps its new shape permanently. Explain why the panel keeps its new shape and why this behaviour is different from what would happen if the panel had only been bent slightly by a much smaller force.

> Edexcel GCSE Physics (1PH0) — 15.1 Forces and matter (Phys only) · Explain · 4 marks

> In car manufacturing, metal panels are shaped by applying very large forces to flat sheets of steel. The finished panels do not spring back to their original flat shape after the force is removed.

## Mark scheme (4 marks)

1. The large force exceeds the elastic limit of the steel
2. This causes plastic distortion / plastic deformation of the steel
3. So the panel does not return to its original shape when the force is removed
4. A smaller force would only cause elastic distortion, so the panel would return to its original flat shape when the force was removed

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