An engineering team tests the reaction time of an emergency safety-shutoff mechanism using a calibrated vertical drop-bar. In a series of trials, the mean distance the drop-bar fell before the brake fully engaged was 18.5 cm.
Calculate the average reaction time of the shutoff mechanism. Give your answer to 2 significant figures.
Use the equation:
time2=distance490 \text{time}^2 = \frac{\text{distance}}{490} time2=490distance39 exam-style questions on Edexcel GCSE Physics 2.5 Stopping and braking distances, covering 2.5.1 Stopping distance and reaction time, 2.5.2 Factors affecting stopping distance, 2.5.3 Dangers of large decelerations, and 2.5.4 Braking distance and initial speed. Each one has a worked solution and a mark scheme showing where the marks go.