Calculating mass from potential energy a skier with a potential energy of 137,200 j waits on top of a ski jump that is 200 m high. what is the mass of the skier? 20 kg 70 kg

(**i would really appreciate if this was answered soon** ) which pair of quantities includes one quantity that increases as the other decreases during simple harmonic motion?

Need only answer if you think you know it

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.