12. A satellite of mass M moves in a circular orbit of radius R with constant speed v . True statements about this satellite include which of the following?
I. Its angular speed is v/R.
II. Its tangential acceleration is zero.
III. The magnitude of its centripetal acceleration is constant.
(A) I only
(B) II only
(C) I and III only
(D) II and III only
(E) I, II, and III
(A) I only
(B) II only
(C) I and III only
(D) II and III only
(E) I, II, and III