AQA · GCSE · Physics · Higher
Elastic potential energy stored in the spring calculation
When the gymnast lands on the floor, one of the springs compresses by 1.2 cm.
text{spring constant} = 8500\ text{N/m}
Calculate the elastic potential energy stored in the spring. Give the unit.
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Marking points
- 1 Converts 1.2 cm to 0.012 m.
- 2 Uses Eₑ = ½ke² with the supplied spring constant and compression.
- 3 Obtains 0.612 (0.61 allowed).
- 4 Supplies J or joule in the separate Unit field.
Full-mark answer
Convert the compression: e = 1.2 cm = 0.012 m. Eₑ = ½ke² = 0.5 × 8500 × 0.012² = 0.612 J.
Why this answer loses marks
I used the compression in centimetres directly.
The deformation must be converted to metres before it is squared in the elastic-energy equation.