Posted by trace on .
A CD has a diameter of 12.0 cm and a mass of 15.8 g. The motor in
a CD player causes the disk, initially at rest, to spin. When in operation, the CD spins in such a way
that the laser scans the tracks at a constant tangential velocity of 1.20 m/s. The first track of the CD is
at a radius of 20.0 mm from the centre of the disk. Calculate the work done by the motor in the CD
player in bringing the disk from rest to the proper speed to read the first track. You may ignore the
small circular hole at the CDâ€™s centre. [Hint: Recall the work-kinetic energy theorem.]