Gravity and the Rotation of Galaxies

[sweet-stuff]

hey i need help! We are doing a lab on the above title and I have no idea how to do it.
So there are few questions i wanted to know to ace this lab. lol i will really appreciate it if someone can help me.

- Describe the differences between the two sets of data. Is the observed speeds explained by the equation
v = √Gm_g/ r ? Justify your answer

-Briefly describe some of the methods astronomers use to estimate the mass of a galaxy, its radius and the value of G.


Please, it will be really helpful if someone can help me!

 

[Chronos]

Galaxy mass, usually by virial theory. Radius by observation. Both methods are approximate. G is assumed. Wiggle G and any result is possible.