A force of 4.0 N produces an extension of 20 mm in a spring that obeys Hooke's law. Use F=kxF=kxF=kx and E=12kx2\displaystyle E=\frac{1}{2}kx^2E=21kx2. What is the work done in stretching the spring from zero extension?
80 J80\ \mathrm{J}80 J
0.080 J0.080\ \mathrm{J}0.080 J
0.040 J0.040\ \mathrm{J}0.040 J
40 J40\ \mathrm{J}40 J
102 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.