Changes in Momentum

• What can forces do to an object?

  Speed up or slow down the object
• What is momentum equal to?

  Mass times velocity
• If a two-kilogram particle travels at five meters per second, what is its momentum?

  10 kilogram meters per second
• What happens to momentum when a force is applied in the same direction as motion?

  Momentum increases due to acceleration
• What is the new momentum of a two-kilogram particle traveling at eight meters per second?

  16 kilogram meters per second
• How do you calculate the force required to change momentum?

  Force equals change in momentum divided by time
• If the change in momentum is 6 and the time is 0.5 seconds, what is the force applied?

  12 newtons
• What is the mass of the ball in the second example?

  600 grams
• What is the initial velocity of the ball in the second example?

  Zero, it starts at rest
• What is the final momentum of a 600-gram ball accelerated to 14 meters per second?

  1. 4 kilogram meters per second
• How do you calculate the force required to accelerate the ball in the second example?

  Use the equation for force
• What happens to momentum during a car crash?

  Momentum decreases to zero almost instantly
• Why is it important to spread the change in momentum over time during a crash?

  To reduce the force experienced by occupants
• What safety features help reduce injury during car crashes?

  • Crumple zones
  • Seat belts
  • Airbags
  • Helmets
  • Crash mats
• How do crumple zones function in a car?

  They absorb impact and extend stopping time
• What are the two functions of seat belts?

  Prevent ejection and slow down occupants
• How do airbags help during a collision?

  They compress to slow down momentum loss
• What is the key principle behind safety systems like helmets and crash mats?

  They increase time for momentum loss
• What is the overall effect of increasing the time it takes for momentum to be lost?

  It results in a lower force acting on a person
• What is the final takeaway from the video?

  Forces change momentum and affect safety