Is a higher or lower impulse better for car crashes?

A 1000lb car travelling at 50mph crashes into another car head on...?

• I don't take physics so this will probably appear dumb to all you physics gods but anyway. A 1000lb car travelling at 50mph crashes into another car head on which weighs 500lb but is travelling at 100mph. Which car moves in which direction? Try and include a giant load of unnecessary formulas to make me look like a BAMF when I give my answer please

• Answer:

  It depends on how elastic the collision is. If there is some amount of elasticity, the cars will "bounce" away from each other. If the collision is completely inelastic, the cars will move together as a single unit following the collision. That's the simplest case to consider: total(p(before)) = total (p(after)) sum (m(x)*v(x)) = sun (m(x)*v(x)) 1000lb * (-50mph) + 500lb * (100mph) = 1500lb * x mph 0 lb mph = 1500lb * x mph x = 0 So the momenta of the two cars cancel. If the collision is inelastic, they will remain stationary. If the collision is elastic, then the lighter car will move away at twice the velocity of the larger car, and that velocity will be between 0 and 100mph.