What do scientists use to divide the geologic time scale? major divisions in the fossil records major divisions in the sedimentary rock layers evidence for catastrophic events in earth's history major changes in mineral deposits in the rock layers

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.