An engineer is testing a heavy-duty spring designed for a maritime mooring system. The tension T T\,T applied to the spring (measured in kilonewtons, kN\text{kN}kN) and the corresponding extension xxx (measured in millimetres, mm\text{mm}mm) are recorded in the table below.
| Tension TTT (kN\text{kN}kN) | Extension xxx (mm\text{mm}mm) |
|---|---|
| 1.2 | 4.2 |
| 2.4 | 8.4 |
| 3.6 | 12.6 |
| 4.8 | 16.8 |
| 6.0 | 21.0 |
| 7.2 | 25.2 |
An apprentice reviews the data and writes this conclusion:
"The extension of the mooring spring is directly proportional to the tensile force applied to it."
Comment on the apprentice's conclusion.
23 exam-style questions on Edexcel GCSE Physics 15.1 Forces and springs, covering 15.1.1 Elastic and inelastic distortion, 15.1.2 The spring constant, 15.1.3 Work done in stretching a spring, and 15.1.4 Linear and non-linear force–extension. Each one has a worked solution and a mark scheme showing where the marks go.