An autonomous delivery rover of total mass m m\,m is travelling at a constant speed v v\,v along a horizontal track. Its collision-avoidance sensors have a latency (reaction time) of τ \tau\,τ seconds before they can trigger the brakes. Once triggered, the brakes apply a constant opposing braking force F F\,F until the rover comes to a complete stop.
Which of the following modifications would increase the total stopping distance of the rover by the greatest factor?
Doubling the total mass mmm of the rover
Doubling the sensor latency time τ\tauτ
Doubling the initial speed vvv of the rover
Reducing the constant braking force FFF by half
39 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.