Center of Mass (COM) is also referred to as Center of Gravity (COG). If the car were picked up by a string from the center of mass it could be suspended in any angle or direction. It is about this point that all forces from the tires and suspension ar linked to the chassis from a geometric perspective. Finding the center of mass requires scaling the car at ground level then scaling the car a second time with one end raised, then using trigonometric functions to calculate the center of mass (or gravity). 
