Torque

Torque is the result of a force moving an object around a pivot point. Torque is calculated by multiplying the applied force times the distance from the pivot point. Since nearly every motion on a VEX robot involves moving an object around a pivot point, this is an important concept.

Picture (or better yet actually do this) a yard/meter stick. You are holding the stick horizontally and holding it on its end. The stick's pivot point is where you are supporting it. Gravity is the force and it is being applied to the center of gravity of the stick and causes it to rotate down. If you keep the stick from rotating down, you are applying a counter force upward at a distance from the pivot point where you hand is holding on the end of the stick- this is torque and counter torque. Next place a small rock on the stick near your hand and then slide the rock down the stick. Gravity will be forcing both the stick and the rock down. As you slide the rock away from the pivot point the distance increases and you will need to apply a larger counter torque to hold the stick up. If you apply more force (counter torque) to the stick, it will move in an arc upward. The further the rock is out on the stick the bigger of an arc it will travel and the more distance the rock will move, but more counter torque will be required. This basic principle affects wheels, gears, sprockets, arms, and anything else which moves around a pivot point.

VEX Robotics Curriculum on Classic Mechanics click <here>