In a mechanical test, a high-precision helical spring inside a fuel-injector valve is subjected to an increasing compressive force. A technician observes that the compression of the spring eventually reaches a strict physical limit and cannot be compressed any further, even when the applied force is increased significantly.
State the physical change in the spring's geometry that prevents any further compression.
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.