Originally Posted by
araveugnitsuga
You eliminate the person behind them. By making cars rigid you are actually letting the problem solve itself.
At the inverse, if the car is front heavy: gravity will have a greater torque on the back because it's farther away from the centre of mass; making it fall trunk first but it is somewhat more complex. See below.
If it falls parallel to the floor torque will make it rotate because the centre of mass is not in the exact centre; assuming the car faces the left it, will rotate clockwise.
Because gravity keeps constant direction and torque is defined in terms of distance from the centre of mass rotating decreases the distance between the trunk and the centre of mass. Because the front DOES have more mass, the force on the front will be slightly bigger and there comes a point where the distance of the back is overpowered by the increased mass on the front making torque go the other way and making the car accelerate counter-clokwise, this in turn increases the distance which will eventually overpower the mass and make it rotate clockwise.
Repeat for a while until it either crashes or some interesting thing which would pop up if I did the calculations happens, said interesting thing might probably be a fixed angle where both effects cancel and the torques remain from that point in constant cancellation, angular velocity and acceleration equal to 0, that or air resistance or terminal velocity make things happen.