Physics
posted by John .
Our sun rotates in a circular orbit about the center of the Milky Way galaxy. The radius of the orbit is 2.2 1020 m, and the angular speed of the sun is 1.2 1015 rad/s.
(a) What is the tangential speed of the sun?
m/s
(b) How long (in years) does it take for the sun to make one revolution around the center?
y

a) V = (angular velocity) x (orbit radius)
b) Period = 2 pi/(angular velocity)
The answer will be in seconds, so you must convert that to years by dividing my the number of seconds in a year. 
34.67

a. 264000

a. Vt= w*r
= (1.2*10^15)*(2.2*10^20)
= 264000 m/s
b. w= period/time
1.2*10^15= 2pi/t
t= 5.2*10^15 seconds
t= 1.7*10^8 yrs