Can a Particle Sliding on a Rotating Rod Decrease in Distance Over Time?

[kojo90]

well, just like the rod produces a perpendicular contact force (N), i would assume, as the ball wants to move radially out, there would be some friction involved. Or does the fact that the problem says, "slide along the rod freely" tell us to ignore this?

 

[voko]

Yes, "slide freely" means "no friction".