To determine the speed of a longitudinal wave pulse in a tensioned steel cable, a group of students stretch a 45 m cable between two fixed anchors. One student strikes one end with a hammer to initiate a wave pulse. A second student, standing at the far end, starts a manual stopwatch when they see the hammer strike and stops it when they feel the vibration arrive.
They record the following travel times across four successive trials:
Explain why the recorded times vary so significantly between trials.
64 exam-style questions on Edexcel GCSE Physics 4.1 Wave properties, covering 4.1.1 Waves transfer energy and information, 4.1.2 Frequency, wavelength, amplitude, period and wavefronts, 4.1.3 Longitudinal and transverse waves, 4.1.4 The wave speed equations, 4.1.5 Measuring wave velocity, and 4.1.6 Calculating depth or distance from waves. Each one has a worked solution and a mark scheme showing where the marks go.