Astring is wrapped around a uniform disk of mass m = 1.2kg and radius r = 0.11m. attached to the disk are four low-mass rods of radius b = 0.14m, each with a small mass m = 0.4kg at the end. the device is initially in rest on a nearly frictionless surface. they you pull the string with a constant force f = 21n for a time of 0.2s. now what is the angular speed of the apparatus?