Changes in Momentum

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

  Force due to change in momentum
• How do safety features like seat belts reduce dangers?

  They reduce the forces from momentum changes
• Who is the target audience for this video?

  Triple physics students
• What is momentum calculated by?

  Mass multiplied by velocity
• Why can rapid changes in momentum be dangerous?

  They can create huge forces on passengers
• What do crash test car manufacturers use to design safety features?

  Crash tests
• What happens to the momentum of passengers during a car crash?

  It falls from a large amount to zero
• What is the relationship between force, mass, and acceleration?

  Force equals mass multiplied by acceleration
• How is acceleration calculated?

  Change in velocity divided by time taken
• What is the formula to calculate force from mass and acceleration?

  Force = mass × acceleration
• What does the equation for force in terms of momentum state?

  Force equals change in momentum divided by time
• If a man has a mass of 100 kg and the car stops in 1 second, what is the force acting on him?

  3000 Newtons
• What is the change in velocity if a car traveling at 30 m/s comes to a stop?

  30 m/s
• What happens to forces when momentum changes occur over a longer time?

  Forces acting are reduced
• What are the safety devices that slow down momentum change?

  • Airbags
  • Seatbelts
  • Crash mats
  • Bike helmets
  • Cushion surfaces in playgrounds
• How do safety devices reduce the risk of serious injury?

  By slowing down momentum change
• What is the key idea about rapid changes in momentum?

  They can be extremely dangerous
• What is the significance of the force experienced by a person during a crash?

  It could be fatal
• What is the time taken for the car to stop in the example given?

  1 second
• What does the change in momentum lead to during a crash?

  Huge forces acting on passengers
• Why is it important to understand the change in momentum in physics?

  It helps in designing safety features
• What is the initial velocity of the car in the example?

  30 m/s
• What is the final velocity of the car when it stops?

  0 m/s
• How can we reduce the dangers of rapid changes in momentum?

  By extending the time of momentum change
• What is the relationship between time taken and force experienced during a crash?

  Longer time reduces force experienced