Forces and braking (P2.1.3)

a) When a vehicle travels at a steady speed the resistive forces balance the driving force. (You should also know this is mostly caused by air resistance).

b) The greater the speed of a vehicle the greater the braking force needed to stop it in a certain distance.

c) 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). (A.K.A:  stopping distance= thinking distance+ braking distance).

d) A driver’s reaction time can be affected by tiredness, drugs and alcohol. (You should also know that ditractions affect the drivers ability to react).

e) When the brakes of a vehicle are applied, 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 increase.

Key words:

thinking distance

braking distance

balance

sum of

tirdness, drugs, alcohol

friction force