When forces are exerted on an object, sometimes those forces will cause the object to be stretched, squeezed, or twisted. We define the strength of the force that might cause an object to be stretched, squeezed, or twisted as .

A1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. the spring has an undeformed length of 5 in. and a constant k =25 lb/ft. knowing that the collar is released from being held at a determine, the speed of the collar and the normal force between the collar and the rod as the collar passes through b.