Most reaserchers think modern plate tectonics began about billion years ago

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.

Which change would make the diagram correct?

Match each type of lever with the correct diagram. 1. first-class 2. third-class 3. second-class