A student applies the same force to a spring three times. The measured extensions are 24 mm, 25 mm and 35 mm. Previous measurements at nearby forces suggest the third result is anomalous. Which is the best next step?
Replace the third reading with the first and calculate a mean.
Repeat the measurement at this force and check the apparatus.
Increase the force until the mean extension becomes larger.
Discard all three readings and stop taking further measurements.
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.