You drop a bowling ball off a space boat into a black hole. Has the amount of mass inside the universe increased, decreased, or stayed the same, ignoring the effects of all other changes?
The amount of mass inside the universe has stayed the same, it just moved from the boat into the black hole.
You're really bored at work one day so to entertain yourself you create 1kg of antimatter along with 1kg of matter. Has the mass in the universe increased or stayed the same?
I'm not sure what other effects I should ignore, but the mass would increase. The ball gains relativistic mass as it accelerates towards the black hole.
PS: Assuming the boat isn't falling too (it's still in orbit), dropping the ball does nothing. You need to decelerate it (reduce it's orbital speed) for it to fall into the black hole.
