Force and Braking

• What should you be able to describe by the end of the video?

  Energy changes during vehicle braking
• What are the potential dangers of large decelerations?

  Loss of control and overheating brakes
• What is the stopping distance of a car composed of?

  Thinking distance plus braking distance
• How does speed affect braking distance?

  Higher speed increases braking distance significantly
• What is the formula for calculating kinetic energy?

  Kinetic energy = $\frac{1}{2}mv^2$
• Why is it important to learn the kinetic energy formula?

  It is not provided in the exam
• What happens to kinetic energy when velocity is doubled?

  Kinetic energy quadruples
• What occurs to kinetic energy when a car brakes?

  Kinetic energy converts to thermal energy
• What causes the temperature of the brakes to increase?

  Friction between brake and wheel
• What is required to stop a car traveling at high speeds?

  A large braking force is needed
• What can happen if brakes overheat?

  Driver may lose control of the vehicle
• How long does it take for the car to decelerate to zero?

  10 seconds
• How do you calculate the force needed for deceleration?

  Mass multiplied by acceleration
• What is the acceleration of the car during deceleration?

  $3 \text{ m/s}^2$
• What force is calculated for the deceleration of the car?

  3000 Newtons
• What are the energy changes during vehicle braking?

  • Kinetic energy converts to thermal energy
  • Friction between brakes and wheels increases temperature
  • High speeds require larger braking forces
• How do you estimate forces involved in vehicle deceleration?

  1. Identify mass of the vehicle
  2. Determine initial and final velocities
  3. Calculate acceleration
  4. Use the formula: Force = mass × acceleration