The frequency(/time period) of oscillation for a 2 body spring system

[abelthayil]

Homework Statement

Two masses m1 and m2 are connected by a spring of spring constant k rest on a frictionless surface. If the masses are pulled apart and let go, the time period of oscillation is :

I know the answer is T(time period) = 2∏$\sqrt{((m1*m2)/(m1+m2))*1/k}$.
Can some one help me derive this equation. I know the concept is called reduced mass and think it uses the center of mass as the reference frame.

 

[Spinnor]

See the first two pages of,

http://orca.phys.uvic.ca/~tatum/classmechs/class17.pdf

 

[abelthayil]

Thanks a TON !