Factors Affecting Thinking Distance & Reaction Time (AQA GCSE Physics): Revision Notes
5.8.4 Factors Affecting Thinking Distance & Reaction Time
Speed and Stopping Distances
If a vehicle is travelling at a higher speed, generally the stopping distance increases. However, thinking distance and braking distance increase at different rates.
As the vehicle speeds up, the thinking distance increases at the same rate as the speed. This is because your reaction time doesn't really change, but the speed you are going does. So the higher the speed, the more distance will be travelled during your reaction time.
As the vehicle speeds up, the braking distance increases. This is because as there is more speed, there is more kinetic energy due to . Therefore, as the speed increases, the kinetic energy increases at a higher rate. This means more work needs to be done to transfer the kinetic energy, so more distance is required as long as the braking force is constant .
Stopping distance against speed graphs
We can use these graphs to compare different vehicles and their different stopping distances. If you wanted to find out which vehicle had a shorter stopping distance at a certain speed, this can be read off the graph and then compared:
For 35mph: Blue Vehicle has a stopping distance of 23m
Red Vehicle has a stopping distance of 29m
So the Blue Vehicle had a shorter stopping distance at 35mph.
