braking

• • stopping distance = thinking distance + braking distance
• • thinking distance is the distance travelled by vehicle between seeing hazard and applying brakes
• • braking distance is the distance travelled by vehicle after driver applied brakes
• • reaction time is affected by: drugs, alcohol, tiredness, distractions
  • longer reaction time increases thinking distance when stopping from speed
• • braking distance is affected by:
  • speed
  • weather
  • condition of tyres
  • how good brakes are
• • the faster vehicle moves, the greater the braking force needed to stop vehicle
  • greater braking force produces greater deceleration
  • the driver may lose control
  • the brakes may overheat
• • in icy weather, there is less grip
  • so, less friction between tyres and road
• • worn brakes creates less force able to be applied to the brakes
  • so, less friction between brakes and wheel
• • thinking distance is affected by speed
  • the faster vehicle moves, the further vehicle travelled when trying to react
• braking:

  • force applied to brakes of vehicles
  • brake pads pressed on wheels
  • causes friction between brakes and wheel
  • so work is done
  • transfers kinetic energy from wheels to thermal energy of brakes
  • reduces kinetic energy of vehicle so slows down
  • increases temperature of brakes
• braking:

  • the faster the vehicle, more energy is in kinetic energy stores
  • so more work done needed
  • so greater braking force needed