Vehicle mass: What effet does it have in an accident?

[AussieAV]

Originally Posted by sudszy

Lets see: If the velocity goes from +100km/h to 10km/h in the opposite direction, we have a change in velocity of 110km/h, if it just comes to a stop in then its only a 100km/h change in velocity, that's a higher change in velocity when it "bounces", fairly straight forward isnt it?

the former creates a higher deacceleration (assuming collision time is equal) since acceleration is the rate of change of velocity for both the car and the occupant, assuming of course they are wearing a seat belt.

Claiming "excess" momentum is converted into deacceleration is nonsense. Momentum is not converted into other quantities, it is conserved/transferred shared amongst other bodies in the collision.

Actually sudzy, I think I've just realised exactly where the flaw in your argument is - it's the assumption that collision time is equal. The car can't just travel in the opposite direction instantaneously. At some point its travelling 1km/hr, then 2km/hr etc up to the point of 10km/hr in the opposite direction (as per your example). This can't happen in zero time.

If you dispute this as well, them please PM me and we'll continue the debate in private.