A string is wrapped about a disk of mass m = 1.8 kg and radius R = 0.12 m. Beginning from rest, you pull the string having a constant force F = 8 N all along a nearly frictionless surface. At instant if the center of the disk has moved a distance x = 0.13 m, a length d = 0.26 m of string consists of unwound off the disk.
i) At this instant, determine the speed of the center of mass of disk?
ii) At this instant, determine how much rotational kinetic energy does the disk encompass relative to the center of mass?