A CD spins at a constant angular velocity of 5.0 revolutions per second counterclockwise. Which of the following statements about the CD is true? A. A net torque acts on it clockwise to keep it moving.
B. A net torque acts on it counterclockwise to keep it moving.
C. No net torque acts on it at all.

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b. b. at twice the distance, the magnitude of the field is 2b. c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.