CHAPTER 15

Gravitation and Circular Motion

1 . A binary star system consists of two identical stars each with a mass of M that orbit each other about
the center of mass of the system as shown. The orbital velocity of the stars is

(A)         

(B)

(C)

(D)

(E)

2 . A sprinter runs around an oval track at a constant speed, starting at point A, proceeding around the
track counterclockwise, and returning to point A. Which graph best represents the magnitude of the
sprinter’s acceleration as she runs one complete lap?