# Shoot a bullet at a half-infinite isotropic elastic solid.

1. Dec 9, 2011

### Spinnor

Say we shoot a bullet that travels in the theta = 0 direction (we are in spherical coordinates). Say the bullet strikes and sticks to a half-infinite isotropic elastic solid that begins at the theta = 90 degrees plane. Is it true that longitudinal waves generated by the bullets impact will be of maximum intensity in the theta = 0 direction and that transverse waves generated by the bullets impact will be of maximum intensity in the theta = 90 degrees direction?

Is there any way, however contrived, that we can reduce or eliminate the longitudinal waves generated by the bullets impact by changing the properties of the isotropic elastic solid while at the same time leaving the transverse waves unaffected?

Thanks for any help!

2. Dec 10, 2011

### Spinnor

If we add an extra dimension I think we can get close to my requirements,

"Is there any way, however contrived, that we can reduce or eliminate the longitudinal waves generated by the bullets impact by changing the properties of the isotropic elastic solid while at the same time leaving the transverse waves unaffected?"

Let us have an 3D infinite isotropic elastic solid which lies in 4D space. Let w be the extra spacial dimension. At equilibrium let the solid be located at w = 0. Let the gun be located at the point (0,0,0,L). Let the bullet be fired so that it only has momentum in the -w direction. Let the bullet strike and stick to the infinite solid at the point (0,0,0,0). A transverse wave propagates outward from the point (0,0,0,0)? There are no longitudinal waves?

Thanks for any help!

Last edited: Dec 10, 2011
3. Dec 10, 2011

### Spinnor

Let us add an extra dimension v. Let there be two guns that shoot bullets in the v and w directions which strike and stick to the solid. With two guns we can produce circularly polarized transverse waves with the right gun shots?

Thanks for any help!