Calculating stopping distances

• What is the importance of stopping vehicles quickly in an emergency?

  It is important to prevent accidents and ensure safety.
• What factors affect stopping distances for vehicles?

  Driver's reactions, road and vehicle conditions, mass, and speed.
• What are the components of stopping distances?

  • Thinking distance
  • Braking distance
• How does thinking distance vary with speed?

  Thinking distance is proportional to the starting speed.
• Why does braking distance increase when speed doubles?

  Because the work done to stop the vehicle removes all of its kinetic energy.
• What is the formula for work done in bringing a vehicle to rest?

  Work done = braking force × distance
• What is the formula for kinetic energy?

  Kinetic energy = \(\frac{1}{2} \times \text{mass} \times (\text{velocity})^{2}\)
• How is braking distance related to velocity?

  Braking distance is proportional to the square of the velocity.
• If a car travels at 12 m/s with a reaction time of 0.5 s, what is the thinking distance?

  Thinking distance = 6 m
• What is the braking distance for a car with a mass of 900 kg and a braking force of 2,000 N traveling at 12 m/s?

  Braking distance = 32 m
• What is the total stopping distance for a car with a thinking distance of 6 m and a braking distance of 32 m?

  Stopping distance = 38 m
• How do you calculate the stopping distance for a car traveling at 24 m/s with a reaction time of 0.5 s?

  Stopping distance = 142 m
• What is the formula to estimate braking force needed to stop a car?

  Braking force = \(\frac{1}{2} \times \frac{m \times v^{2}}{d}\)
• What is the estimated braking force needed to stop a family car from its top speed in 100 m with a mass of 1,600 kg and speed of 27 m/s?

  Braking force is approximately 5,800 N
• What is the estimated braking force needed to decelerate a lorry from its top speed in 100 m with a mass of 36,000 kg and speed of 22 m/s?

  Braking force is approximately 87,000 N
• What are the key formulas related to stopping distances?

  • Work done = braking force × distance
  • Kinetic energy = \(\frac{1}{2} \times \text{mass} \times (\text{velocity})^{2}\)
  • Stopping distance = thinking distance + braking distance