A rifle of mass 4.0 kg fires a 12.0 g bullet. If the bullet travels at a velocity of 1,500.0 m/s, what is the recoil of the gun?

Explanation:

Conservation of momentum

Initial momentum is zero as both gun and bullet are motionless in the frame of reference before firing.

0 = 0.012(1500.0) + 4.0v

v = - 4.5 m/s

Must be a rail gun as the fastest powder driven bullets are moving at roughly half the speed described.

wavelength divides in half and speed stays the same.