Physics/Dynamics
posted by Kyle .
A series of small packages are being moved by a thin conveyor belt that passes over a 300mm radius idler pulley. The belt starts from rest at time t=0 and its speed increases at a constant rate of 150mm/s^2. Knowing that the coefficient of static friction between the packages and the belt is 0.75, determine the time at which the first package slips.
The given answer is 11.32 seconds.

The friction force on a package not slipping must be M*0.15 m/s^2, and the maximum static friction force is M*9.8 m/s^2. I don't see why slipping would ever occur, or what the radius of the "idler pully" bas to do with the problem.