Braking distance

• Entry Level Certificate
• Braking distance


  The distance a car travels whilst braking
• Thinking distance


  The distance a car travels whilst the driver reacts
• Stopping distance


  The distance it takes for a vehicle to stop, which is the thinking distance and the braking distance added together
• A moving car has lots of energy in its kinetic energy store
• It needs friction from car brakes to stop
• When a car stops, car brakes do work to transfer energy from the kinetic store to the thermal energy store of the surroundings
• A fast car has more energy in its kinetic store than a slower car
• More work has to be done to stop a car with more kinetic energy
• As speed increases


  Braking distance increases
• Factors that affect thinking distance

  • The driver's reaction time
  • The speed of the car
• Factors that affect braking distance

  • The speed of the car
  • Friction
  • The mass of the car
  • The condition of the brakes and tyres
• It is now illegal in the UK to use your mobile phone whilst driving
• Worn brake pads or tyres will increase the braking distance because there is less friction force
• Anything that increases reaction times will increase the thinking distance
• The braking distance will be shorter when there is more friction
• There is less friction on wet or icy roads
• A faster moving car needs more force to slow it down
• It takes more force to stop a heavier car
• All of these factors will increase the stopping distance of a car
• Investigate how talking to someone affects your reaction time
• Choose the correct words from the box to complete the following sentences
• What is stopping distance?