Thread: Tell me how to calculate these two astronomy questions

As much as I hate to use DV as my own personal network of tutors, I'm a highschool junior with my first college exam on Thursday and I could use some help.

1. A certain binary system is composed of two identical main sequence stars in circular orbit. The stars are separated by 3x10^8 km. Each star has a mass of 6x10^30 kg. What is the orbital period of the system?

2. The H-alpha Balmer line (656.3 nm) in the spectrum of a star is observed at a photon frequency of 456.5 Tera-Hz. What is the star's radial velocity? Is the star approaching or receding? Is the star red-shifted or blue shifted?

The first has something to do with Kepler's laws. But I don't know how to apply them. And these symbols! What do all these symbols mean!?!?. Help me, DV!