Question

when a bullet is fired from a gun, what is true about the momentum? the bullet has more momentum than the gun, so momentum is not conserved. the bullet and gun have equal momenta in opposite directions, so the systems momentum is conserved. the bullet and the gun have equal momenta in the same direction, so the systems momentum is conserved. the gun has more momentum than the bullet, so the momentum is not conserved.

Explanation:

According to the law of conservation of momentum, in the absence of external forces (assuming the firing of the bullet is an internal force - dominated event), the total momentum of the system (bullet + gun) before firing is zero (both are at rest). After firing, the momentum of the bullet \(p_{bullet}=m_{bullet}v_{bullet}\) and the momentum of the gun \(p_{gun}=-m_{gun}v_{gun}\) (negative because it recoils in the opposite direction). The sum of their momenta \(p_{bullet}+p_{gun}=0\), meaning \(|p_{bullet}| = |p_{gun}|\) (equal magnitudes, opposite directions).

Answer:

The bullet and gun have equal momenta in opposite directions, so the system's momentum is conserved.