1. 1
   A bus travels along a straight, flat motorway at a constant speed of 25 m/s, carrying commuters during the morning rush hour.

   (a)

   Which statement correctly describes the forces acting on the bus at this steady speed?

   [1 mark]

   • AThe driving force from the engine exactly balances the resistive forces
   • BThe driving force from the engine is greater than the resistive forces
   • CThere are no resistive forces acting on the bus
   • DThe resistive forces are greater than the driving force

   (b)

   The bus driver then presses the accelerator further to increase the bus's speed to 30 m/s on the same flat motorway. Once the bus reaches this new steady speed, how do the resistive forces acting on it compare with those at 25 m/s?

   [1 mark]

   • AThe resistive forces are the same, since the road surface hasn't changed
   • BThe resistive forces are smaller at the higher speed
   • CThe resistive forces are greater at the higher speed
   • DThere are no resistive forces once the bus reaches a steady higher speed

   (c)

   Explain why the bus driver needs to apply a greater braking force to bring the bus to a stop in a given distance when travelling at 30 m/s compared with 25 m/s, and describe one risk to the bus's braking system that can result from repeated hard braking from high speed.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A road safety campaign tests a driver's reaction time using a simple hazard-perception exercise on a driving simulator, comparing the same driver when well rested and again after being kept awake all night.

   (a)

   Which quantity would you expect to increase due to tiredness?

   [1 mark]

   • ABraking distance only
   • BThinking distance
   • CThe vehicle's top speed
   • DThe vehicle's mass

   (b)

   The campaign also compares reaction times for drivers who have consumed alcohol with those who have not. Which term describes the total distance a car travels from the moment a driver first sees a hazard to the moment the car comes to a complete stop?

   [1 mark]

   • ABraking distance
   • BThinking distance
   • CReaction distance
   • DStopping distance

   (c)

   The campaign's data shows that a driver who has consumed alcohol has a longer thinking distance than a sober driver travelling at the same speed. Explain why alcohol increases thinking distance, and state two other factors, besides alcohol and tiredness, that can affect a driver's reaction time.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A driving instructor explains stopping distance to a learner driver during a lesson on a quiet country road, using the example of braking to avoid a stray animal that runs into the road.

   (a)

   A driving instructor explains to a learner driver that stopping distance is made up of two parts: thinking distance and braking distance. Define each of these two terms, and explain what happens to the kinetic energy of the car as the brakes are applied and the car slows down.

   [3 marks]

   (b)

   Later in the lesson, it begins to rain heavily and the road surface becomes wet. Explain why the learner driver's braking distance is likely to be greater in these conditions than on a dry road at the same speed, and describe one other factor relating to the condition of the vehicle itself (rather than the weather) that could also increase braking distance.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A national road safety authority is designing a public awareness campaign to reduce accidents caused by drivers travelling too fast for the conditions on rural roads during winter, when roads are frequently wet or icy.

   (a)

   Explain, using ideas about stopping distance, thinking distance and braking distance, why driving at a lower speed is particularly important on wet or icy rural roads, and why the effect of speed on stopping distance is not simply proportional (i.e. why doubling speed does not just double the stopping distance).

   [6 marks]

   (b)

   The campaign also wants to explain to drivers why a well-maintained car is important for safety, even for an experienced and alert driver with a fast reaction time. Explain, referring to both thinking distance and braking distance, why a driver's skill and alertness alone cannot fully compensate for a poorly maintained vehicle or dangerous road conditions.

   [6 marks]

   Total for question 4: 12 marks

End of questions