Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What are poor vehicle conditions limited to?
   • they are limited to brakes or tyres.
2. What is the definition of stoppong distance?
   • The stopping distance of a vehicle is the sum of the distance the vehicle travels during the driver?s reaction time (thinking distance) and the distance it travels under the braking Force (braking distance).
3. What can the braking distance of a vehicle be affected by?
   • It can be affected by adverse road and weather conditions and poor condition of the vehicle.
4. What affect would an increased speed for a given breaking force have on stopping distance?
   • Stopping distance would be greater.
5. What are adverse road conditions?
   • wet, icy, potholes and uneven surfaces are considered to be adverse road conditions.
6. Does every person have the same reaction time? Explain
   • No, reaction times vary from person to person.
7. What is the typical value range for the reaction time of a typical person?
   • The typical values range from 0.2 s to 0.9 s.
8. How can a driver's reaction time be affected?
   • A driver's reaction time can be affected by tiredness, drugs and alcohol.
9. (Physics only) How does the distance for a vehicle to make an emergency stop vary over a range of speeds typical for that vehicle.
   • (Physics only) The faster the vehicle is going the greater the distance would be to come to a stop.
10. What else could affect a driver's ability to react?
    • Distractions such as mobile phones or other people in the car.
11. Whatwould the estimate of the distance required for road vehicles to stop in an emergency varies over a range of speeds be; 30mph, 40mph and 60mph?
    • 30mph - 23m 40mph - 36m 60mph -73m
12. (Physics only)
    • (Physics only)
13. What methods could be used to measure human reaction times?
    • How quickly a person can click on seeing a specified object, catching a ruler when it is dropped.
14. When a force is applied to the brakes of a vehicle, how does the work done by the forces between the brakes affect the kinetic energy and temperature of the brakes?
    • When a Force is applied to the brakes of a vehicle, work done by the friction Force between the brakes and the wheel reduces the kinetic Energy of the vehicle and the temperature of the brakes increases.
15. How could you interpret and evaluate the following results; person A had a reaction time of 3s, Person B had a reaction time of 4s and person C has a reaction time of 9s?
    • Person A and B had similar reaction times but person C was very much slower by 5-6s, they may have had a factor that affected their reaction time and therfore it may be useful to repeat to gain more results.
16. what is the relationship between the speed of a vehicle and the braking force needed to stop the vehicle?
    • The greater the speed of a vehicle the greater the braking Force needed to stop the vehicle in a certain distance.
17. How does increasing the braking force affect deceleration and brake heat?
    • The greater the braking Force the greater the deceleration of the vehicle. Large decelerations may lead to brakes overheating and/or loss of control.
18. What are the dangers caused by large decelerations?
    • skidding, tyre blow-outs, loss of control of the vehicle, crashes.
19. (HT only) What is the force if the mass of a vehicle os 2000Kg and the acceleration is 12m/s/s?
    • (HT only) Force = 2000 x 12 = 24000N