lide the more massive car will force the smaller vehicle backwards andthe smaller car will experience more force. This is due to the conservation of momentum. The Law ofConservation of Momentum states that in an isolated system the momentum before a collision is equal to themomentum after the collision, if we disregard friction. So in the example above we can see that themomentum lost by the larger car was gained by the smaller car. If two cars of equal mass collide and all thepotential energy is converted back into kinetic energy after the collision then the collision is said to beelastic. However if the two bodies collide and stick together and continue with the same final speed then wecall it an inelastic collision. Most collisions are neither completely elastic or inelastic. The conservation ofmomentum is often very obvious in a collision on a slippery road where friction is very small. The Law ofConservation of Momentum holds true for collisions in two dimensions also. The total momentum of asystem is equal to the vector sum of the momentum of all parts of the system.For many decades people have used the laws of physic to explain the event of car crashes. Accident reconstructionists are people who devoted their careers to using their knowledge of physics andmotion along with remains from accident scenes to determine the cause of the accident and how it couldhave been avoided. They also work with manufacturers to come up with ways to reduce injuries that occurfrom car accidents. Reconsturctionists use formulas and what they know to determine masses of the vehicle,impact location, rest position, postimpact direction which can be found by studying tire marks and gouges inthe road. The deceleration from impact to rest is found by looking at postimpact braking, rotation, terrain,and contact with roadside brush. A reconstructionists conclusions are very useful for car engineers,manufacturers and consumers. By studying ac...
