A student does a ruler-drop test five times. The table shows the distance the ruler falls before the student catches it each time.
Table
| Trial | Distance the ruler falls (cm\text{cm}cm) |
|---|---|
| 1 | 18 |
| 2 | 20 |
| 3 | 19 |
| 4 | 31 |
| 5 | 17 |
What value should the student use as the mean distance?
14.0 cm14.0\ \text{cm}14.0 cm
19.0 cm19.0\ \text{cm}19.0 cm
18.5 cm18.5\ \text{cm}18.5 cm
21.0 cm21.0\ \text{cm}21.0 cm
50 exam-style questions on OCR GCSE Physics 8.1 Physics on the move, covering 8.1.1 Typical everyday speeds, 8.1.2 Typical everyday accelerations, 8.1.3 Ratios, units and rates on the road, 8.1.4 Human reaction times, 8.1.5 Factors affecting stopping distance, 8.1.6 Stopping distances at different speeds, 8.1.7 Dangers of large decelerations, 8.1.8 Estimating forces in road situations, and 8.1.9 Estimating the effects of large accelerations. Each one has a worked solution and a mark scheme showing where the marks go.