The conditions for stable equilibrium for a system are:
1. The sum of the net force applied to the system must be zero.
2. The sum of the net torque applied to the system must be zero.
This simulation begin with a car motion with constant velocity.
Two different load are placed on top of the car at differnet locations (both are 30.0 down).
Another down force on the car is the mass of the car itself (which is 40.0 down).
The sum of the normal force on front tire and rear tire must balance the above forces.
And the sum of torques must be zero,too.
You can use mouse to drag the load location or tire location and find out how the tension forces are changed.
When you fully understand the above situations,
you can drag slider to add acceleration to the car and study how the normal forces changed.
If the color of the car turn into red, it means that in real situation the car will tilt (car accident!).

Virtual Physics laboratory Original URL

Fu-Kwun Hwang, Dept. Of Physics, National Taiwan Normal University.