When an automobile draiver steps on the accelerator, the nose of the car moves upward. When the driver brakes, the nose moves download.
You can change the accelaration of the car and see how the force were distributed between tires.
You can also drag those vectors(up/down) to change the weight of the car or the weight of the loads.
You also can drag the tire(left/right) to change the position of the tire and see how the loading  were redistributed.

VIEW or DOWNLOAD ejs xml source
then click to translate strings for selected locale.

Press the Alt key and the left mouse button to drag the applet off the browser and onto the desktop.