Weight distrubituion between two cylinders.

[hangainlover]

Homework Statement

I was just websearching and came across this interesting demonstration.
http://demonstrations.wolfram.com/AMassiveBarOscillatingBetweenTwoIdenticalRotatingSupportRoll/

Homework Equations

I wanted to define the normal forces N1 and N2 based on their position x(t) from the center of gravity of the bar. the website says Normal force= w(1/2 ± x(t)/L). I really want to find out how they came up with that equation to define weight distribution.
I really need your help.
Thanks

The Attempt at a Solution

 

[hangainlover]

bump
anyone please?