A string is wrapped around a disk of mass 2.1 kg (its density is not necessarily uniform). Starting from rest, you pull the string with a constant force of 9 N along a nearly frictionless surface. At the instant when the center of the disk has moved a distance 0.11 m, your hand has moved a distance of .28 m
a) At this instant, what is the speed of the center of mass of the disk?
b) At this instant, how much rotational kinetic energy does the disk has relative to its center of mass?
c) At this instant, the angular speed of the disk is 7.5 radians/s. What is the moment of inertia of the disk?