# Car Safety/Momentum

Momentum=

mass

×

velocity

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• Created by: nour123
• Created on: 02-02-14 20:42
• car safety
• Momentum
• The greater the mass of an object the greater the velocity, the more momentum the object has.
• Momentum is a vector quantity just like velocity, it has a size and direction.
• Momentum before = Momentum after.
• Momentum is conserved when no external forces act. Likewise the total momentum after is the total momentum before.
• Remember to always put the direction of the force.
• Positive means to the right.
• Negative means to the left.
• Forces cause change in momentum.
• In a car accident, the momentum of the persons body will change very quickly,  if the forces acting on the bogy are large, it means that there is a likelihood of the person getting injured.
• Force (N) = change in momentum (kg m/s) / time(s)
• If the force is bigger it means that there will be a faster change in momentum and the acceleration will be greater.
• When force acts on an object it causes change of momentum.
• ' the longer it takes for a change in momentum, the smaller the force'
• Prevention of injuries.
• Crumple Zone
• The crumple zone crumples on impact, increasing the time taken for the car to stop. The material crumple and squashes and folds in a certain way to reduce the momentum of the car over a longer period of time.
• The crumple zone can be tested using egg and bubble wrap.
• Seat belts.
• The seat belts help reduce the rate of momentum and the forces actin on the driver or passenger. However if the speed of the vehicle is too fast then the seat belt might cause injury itself. It also increases the time taken for the wearer to stop.
• Air bags.
• Air bags slow the driver down more gradually. The air bags reduce the momentum to zero, which can help prevent seat belt injuries on shoulders.
• Forces cause change in momentum.
• In a car accident, the momentum of the persons body will change very quickly,  if the forces acting on the bogy are large, it means that there is a likelihood of the person getting injured.
• Force (N) = change in momentum (kg m/s) / time(s)
• If the force is bigger it means that there will be a faster change in momentum and the acceleration will be greater.
• When force acts on an object it causes change of momentum.
• ' the longer it takes for a change in momentum, the smaller the force'