How do changes in the mass of an object affect its motions?

if by motion you mean movement then the objects weight would change and it's mass so if it were heavier it might move slower. But if going down at a 145 degree angle then it would it would go slow then become faster as it goes down more. if it were lighter then it would go fast and continue to be fast until stopped by a force more powerful than it's own.

Standard unit of measurement for mass