6.5 Exercise 19

(a) The Sun orbits the Milky Way galaxy once each $2 . \text{60 x 10}^{8} \text{ y}$, with a roughly circular orbit averaging $3 . \text{00 x 10}^{4}$ light years in radius. (A light year is the distance traveled by light in 1 y.) Calculate the centripetal acceleration of the Sun in its galactic orbit. Does your result support the contention that a nearly inertial frame of reference can be located at the Sun?

(b) Calculate the average speed of the Sun in its galactic orbit. Does the answer surprise you?