# Collisions at high speed vs normal speed

1. Sep 6, 2007

### mreznicek

Friends:

I understand that collisions at high speeds cause a lot more damage. Like when micro meteors strike satellites. Can someone explain how this physics differs from normal collisions? At what velocity do these effects become enlarged? I read about an electromagnetic gun whose projectile causes significantly more damage due to the speed of the projectile. Can someone elaborate on how this works?

Thanks amigos, -Migs

P.S. This is not a homework question! I finished M.E. a long time ago!

2. Sep 6, 2007

### DaveC426913

The damage a projectile causes is proportional to its momentum, which is a product of its mass and velocity.

3. Sep 6, 2007

### genneth

Damage is related to the amount of energy imparted. Kinetic energy of a projectile is proportional to the square of the speed, thus at higher and higher speeds the energy grows immensely.

4. Sep 6, 2007

### mreznicek

Guys:

Ok, so at what point does a particle simply "explode" the target rather than simply pass though it. It's hard for me to express what I'm thinking because there clearly seems to be a transition between the particle collisions we learned about in college physics and the phenomena described by these rail guns and micrometeorites.

5. Sep 6, 2007

### mgb_phys

Generally physics problems assume elastic scattering, no energy is lost and the particle bounces off. In high speed collisions the particle is destroyed and energy is very definately transferred to the target.
You could take the speed at which the kinetic energy is sufficent to melt or vapourise the projectile as a good lower limit of an explosive collision.

6. Sep 6, 2007

### mreznicek

There you go! Which again makes it a bit nebulous to really know the velocity... Thanks for the words amigos. -Migs