Hey all. My professor gave us this question in class the other day but I'm having a hell of a time reasoning out how the answer can be true. Firstly, the problem: There's a bucket on wheels moving at a constant velocity on a frictionless surface. It's raining out so the bucket is gaining mass. Will it slow down, speed up, or remain at that velocity as it gains mass? My gut tells me that on a frictionless surface that it'd remain constant, but he told the class that it will slow down and that it doesn't matter if the surface is frictionless or not. It makes perfect sense to me that it'd slow down with friction (becuase as it gains mass, its normal force increases which increases the frictional force). If anybody could help me reconcile this it'd be appreciated. Thanks a lot!