If we consider a rod hanging from the ceiling, able to swing freely, and then fire a bullet that hits its end, it will swing like a pendulum. I know the total linear momentum is not conserved since there is a force acting on the top of the rod. But in what direction is that force acting? I suspect its x-component should be opposite the bullet's direction to stop the rod from just continuing forward together with the bullet. Since the center of mass starts moving upwards as the rod swings, does the impulse have to have some component in the y-direction as well?
What would happen if the rod was just floating in outer space when it was hit, then the force acting on the top wouldn't exist?
Then the linear momentum would be conserved, so would the rod move in the bullet's direction and spin at the same time?
I'm not sure I understand this correctly, so please enlighten me:))
