changes in momentum

• when does a change in momentum occur?

  a force acts on an object that is moving
• how do vehicle safety features (crumple zones, seat belts, airbags) work in relation to the rate & change of momentum

  • they absorb the energy from the impact & increase the time over which the force takes place
  • this increases the time taken for the change in momentum of the passenger & vehicle to come to rest
  • this increased time reduces the force & injury on a passenger
• what does the usefulness of safety equipment depend on?

  mass & velocity
• how do crash mats work in relation to the rate & change of momentum?

  • thick & soft in order to offer shock absorption of the force created by the person landing on the mat
  • increases the contact time over which their momentum is reduced creating a smaller impact force & lower chance of injury
• how do cushioned surfaces work in relation to the rate & change of momentum?

  • increase contact time with ground
  • rate of change of momentum decreases
  • reduces chance of injury