The sun is a satellite of Milky Way's galactic central cluster. The sun revolves around this center with a radius of 2.28x10^20 m. and with a period of 2.52x10^8 years. If the universe is 16 billion years old. a) How many times has the galaxy rotated and b)with what speed is the sun traveling around the galactic cluster in m/s?
r = 2.28 * 10^20
period = 2.52*10*8
16*10^9/2.52*10^8 = 160/2.52 = 63.5 times
period in seconds = 2.52*10^8 yr * 3600 s/hr *24 hr/d * 365 d/yr
circumference = 2 pi (2.28*10^20)
speed = circumference / period