Imagine an object that's fixed at one point but free to rotate. Give it a push. It can't move laterally, since it's fixed at the pivot, but it can begin to spin round and round. Analogous to Newton's laws of linear motion, there's a set of equations governing how fast the spin rate of the object increases. Check out Tipler (p. 227) if this is new to you.

In rotational motion, * Torque* plays the same role as force in linear
motion.
The torque () is defined as the force multiplied by the perpendicular
distance between the force and the pivot.

Thursday October 8 16:09:30 BST 1998