Question

could someone please help me get started with this problem. I am lost

our galaxy has a diameter of about 100,000 light years. and a thickness of about 2000 light years. our sun is locate about 28000 light years from center of our galaxy, and orbits once every 200 million years. calculate the speed of the sun relative to the center of galaxy in km/s. use C=2 r to determine the orbital distance, and pi=3.14.

Answer 1

It's path is supposed to be a large circle, but I drew it messily, sorry!

It's path is the circumference, then. And the problem means to say the the circumference is \(C\) and \(C=2\pi r\). Do you see that? That is the distance, then.

And the time the Sun takes to travel that path is 200 million years.

So you have the time and the distance, so the speed, \(v\), is found by the \(v=\dfrac{d}{t}\) equation!