Center of Mass involving three cubes

[DLPhysics]

Homework Statement

Three cubes, of side l, 2l, and 3lo, are placed next to one another (in contact) with their centers along a straight line and the l = 2lo cube in the center. What is the position, along this line, of the CM of this system? Assume the cubes are made of the same uniform material.

Homework Equations

CM = (m1x1 + m2x2 + m3x3)/ (m1 + m2 + m3)

The Attempt at a Solution

The one thing that stumped me the most was how to find the mass of the object. I'm inferring that since the cubes are all made out of the same material, they have the same density, meaning that the masses have an inverse-square relationship with each other.

And I have trouble determining the positions of the boxes; I always go by the center of the objects, correct?

Damion

 

[DLPhysics]

I figured out the problem on my own! Ahh, it was simpler than I thought it would be.