2009-11-29, 04:19 PM
If it's inelastic or elastic doesn't matter, what matters is how the force is transferred. The surface friction isn't relevant either in a perfect collision.
The less the person compresses, the closer acceleration is to infinity. If he's an ideal solid, it's infinite (doesn't matter if collision is elastic or inelastic). If it penetrates for 10cm or whatever, then there is time for it to slow down, and speed him up - then you need to find how long it takes from initial contact until the projectile has stopped moving relative to the person, and divide the final speed by that time to get the acceleration.
If it's inelastic the final speed is also slightly different - instead of 50kg mass you have a 52kg mass, so 2*200 = 52*x.
The less the person compresses, the closer acceleration is to infinity. If he's an ideal solid, it's infinite (doesn't matter if collision is elastic or inelastic). If it penetrates for 10cm or whatever, then there is time for it to slow down, and speed him up - then you need to find how long it takes from initial contact until the projectile has stopped moving relative to the person, and divide the final speed by that time to get the acceleration.
If it's inelastic the final speed is also slightly different - instead of 50kg mass you have a 52kg mass, so 2*200 = 52*x.