P5: Stopping Distances Physics GCSE

• What is the stopping distance of a car?

  The total distance travelled to stop
• How is stopping distance calculated?

  Stopping distance = Thinking distance + Braking distance
• What is thinking distance?

  Distance travelled during driver reaction time
• What is braking distance?

  Distance travelled under braking force
• What happens to stopping distance as speed increases?

  It increases with greater vehicle speed
• If a car's stopping distance is 40 m and the thinking distance is 14 m, what is the braking distance?

  26 m
• What is the formula for calculating reaction distance?

  Reaction Distance = Speed × Reaction time
• What factors can increase thinking distance?

  Tiredness, distractions, intoxication
• What is the typical range for human reaction time?

  0.2 - 0.9 seconds
• How can human reaction time be measured?

  By dropping a ruler and catching it
• Why is reaction time important in stopping distance?

  It affects the total stopping distance
• What is the relationship between thinking distance and speed?

  Thinking distance is directly proportional to speed
• What additional factors affect braking distance?

  Vehicle condition, road condition, vehicle mass
• What happens to kinetic energy when brakes are applied?

  Kinetic energy is converted to thermal energy
• What is the equation for work done by the braking force?

  Work done = Force × distance
• If a car has a total kinetic energy of 168,750 J and a braking force of 6,000 N, what is the braking distance?

  28.1 m
• How does speed affect braking distance?

  Braking distance is proportional to speed squared
• What happens to braking distance at very high speeds?

  Braking distance increases due to brake inefficiency
• What are the factors affecting thinking distance?

  • Speed of the car
  • Tiredness
  • Distractions (e.g., mobile phone use)
  • Intoxication (alcohol or drugs)
• What are the factors affecting braking distance?

  • Speed of the car
  • Vehicle condition (e.g., worn tyres)
  • Road condition (e.g., wet or icy)
  • Vehicle mass (heavier vehicles take longer to stop)
• What is the process of energy transfer when brakes are applied?

  • Kinetic energy is transferred to thermal energy
  • Frictional force does work on the brakes
  • Brakes heat up as energy is transferred
• What is the significance of Newton's second law in braking?

  • Links resultant force and acceleration
  • Greater speed requires larger braking force
  • Large decelerations can lead to brake overheating