A trolley moves at a steady speed along a horizontal track.
A student uses a stopwatch to time the trolley over a distance of 0.50 m. Each time is about 0.6 s.
Which change would most reduce the effect of the student's reaction time on the accuracy of the speed?
Repeat each timing five times and calculate a mean
Use a stopwatch that reads to the nearest 0.001 s0.001\ \text{s}0.001 s
Measure the distance with a more precise ruler
Time the trolley over a much longer distance
43 exam-style questions on OCR GCSE Physics 2.1 Motion, covering 2.1.1 Measuring distance and time, 2.1.2 Measuring speed, 2.1.3 Ratios, units and rates in motion, 2.1.4 Scalars and vectors in motion, 2.1.5 Distance-time and velocity-time graphs, 2.1.6 Area under a velocity-time graph, 2.1.7 Average speed for non-uniform motion, and 2.1.8 Uniform motion and uniform acceleration. Each one has a worked solution and a mark scheme showing where the marks go.