How much work is done by the motor in a CD player to make a CD spin, starting from rest? The CD has a diameter of 12.0 cm and a mass of 15.8 g. The laser scans at a constant tangential velocity of 1.20 m/s. Assume that the music is first detected at a radius of 31.0 mm from the center of the disk. Use the tangential velocity of the the laser and the radius at which music is first detected to determine the angular velocity of the disc. Ignore the small circular hole at the CD's center.

answer in joules.