View Single Post
Feb28-09, 04:29 PM
Sci Advisor
P: 8,470
Quote Quote by 1bayouboy View Post
I think I'm missing something because at relativistic speeds it takes more energy
to achieve a delta-v, the chemical energy imparted to the bullet is the same...
Well, the delta-v is always the same in the frame where the gun is at rest. In a frame where the gun is moving, the delta-v can be smaller or larger than in the gun's rest frame, depending on whether the bullet was traveling with the gun's direction of motion or against it (see relativistic velocity addition), and the energy imparted by the chemical explosion would also be different in this frame (since the molecules send outward by the explosion can have a higher velocity in this frame, they have greater kinetic energy to impart to the bullet).