A cable that weighs 2 kg per meter is used to lift 400 kg of coal up a mineshaft 100 meters deep. However, when it reaches a height of 50 meters, it knocks against the wall and loses 20 kg of coal. How much work is required to lift it all the way from the bottom to the top

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.