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 12.70 cm and a mass of 16.30 g. the laser scans at a constant tangential velocity of 1.150 m/s. assume that the music is first detected at a radius of 20.90 mm from the center of the disk. ignore the small circular hole at the cd's center.

Which statement is true if the refractive index of medium a is greater than that of medium b? a. total internal reflection is possible when light travels from air to medium b to medium a. b. total internal reflection is possible when light travels from medium a to medium b. c. total internal reflection is possible when light travels from medium b to medium a. d. total internal reflection is possible when light travels from air to medium a. e. total internal reflection is possible when light travels from air to medium b.