Posted by sara on .
A string is wrapped around a uniform disk of mass M = 1.6 kg and radius R = 0.10 m. (Recall that the moment of inertia of a uniform disk is (1/2)MR2.) Attached to the disk are four low-mass rods of radius b = 0.17 m, each with a small mass m = 0.6 kg at the end. The device is initially at rest on a nearly frictionless surface. Then you pull the string with a constant force F = 23 N. At the instant when the center of the disk has moved a distance d = 0.047 m, a length w = 0.024 m of string has unwound off the disk.
You keep pulling with constant force 23 N for an additional 0.032 s. Now what is the angular speed of the apparatus?
should be 15, 20, .3