I caught mine and #2's error. I mixed my frames of reference, so I didn't take into consideration the component of the projectile's momentum along the direction in which the cart is traveling. Cool. Number 1 wins. Thank you for the hints, tiny-tim.
I apologize. I'll stick to x,y,z. lol.
It shouldn't. Net forces cause accelerations, not changes in mass. If the floor is frictionless and a cart is moving at a constant speed, me removing a mass shouldn't make it go faster or slower. This is what I think, but the conservation of momentum...
I think the second person is right. Conservation of momentum is valid just because there is no external net force acting on the entire system. The momentum in both components should be conserved then. This means that the mass thrown off the cart should be compensated with a greater cart velocity...
Homework Statement
You are on a cart going at a constant velocity on a frictionless surface. You toss something off the cart in a direction that is perpendicular to your motion, thus lowering the mass of the cart/you system. Does the speed in the horizontal direction change?
Person 1...