If two cars were at the top of a uniform slope, and the cars are identical in every way other than their mass, which one would reach the bottom first? and why? This is an argument that lasted all the way from inverness to dundee, and still hasn't been settled, even though there are about 100 people involved now. I need someone to settle it before it escalates further. I personally think the lighter one would get to the bottom first as the friction would be greater for the heavier one from the tires being spread; although i'm not sure if the momentum of the heavier car, once it picked up some speed, would outweigh friction and air resistance.