posted by Phys on .
A stationary 50 kg circular object (r0=.25m) is on a 30 degree incline. The coefficient of rolling friction between the block and the incline is 0.05. If it moves for 3 seconds, what is the angular displacement of the object at this time?
It depends upon what type of circular object it us. Is it a disc, a sphere, a spherical shell or a wheel with most of mass on the outer rim? Why are they asking for angular displacment rather than linear motion?
Is the object rolling down the incline, starting from zero speed?
The rolling friction will cause a motion-opposing force of M g cos 30 * 0.05 = 21.2 N
The net accelerating force is
F = M g sin 30 - 21.2 N = 224 N
The moment of inertia of the object needs to be taken into account when predicting the motion