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Wheelies     Along with normal wheelies, there is another type of wheelstand in Monster Truck Jam: the slap wheelie. A normal wheelie starts from rest and the truck must accelerate very rapidly in order to shift its weight further back. The least acceleration is needed when the center of mass is towards the rear of the truck because it is proportional to how far forward the mass is. Since the acceleration is inversely proportional to height, it is best to have the center of mass higher up. A slap wheelie is different in that it occurs after a jump. Right after the truck lands, the front wheels hit the ground and bounce back up into a wheelie. This means that the driver must time perfectly when he hits the gas pedal in order to use the torque of the engine for a successful wheelstand. Most of the trucks are equipped with a wheelie bar in order to prevent them from rolling over backwards.

Doughnuts     A doughnut is when a truck rotates in circles very fast creating a doughnut-like shape. Monster trucks are especially good at these because they have four wheel steering. This allows them to turn extremely tightly around their front inside tier. As they rotate, the tuck tends to lean outwards and can easily flip out of control.

http://www.caranddriver.com/features/the-physics-of-monster-trucks-feature