A student attaches a block of mass M to a vertical spring so that the block-spring system will oscillate if the block-spring sys
tem is released from rest at a vertical position that is not the system’s equilibrium position. The figure shows three positions of the spring as it travels from point X to point Y and then from point Y to point Z . Point X is the lowest point of the center of mass of the block as it oscillates. Point Y is the equilibrium position of the block-spring system. Point Z is the highest point of the center of mass of the block as it oscillates. The gravitational potential energy of the block-spring-Earth system is considered to be zero at point X . Which of the following claims is correct about the block-spring-Earth system? A) The gravitational potential energy of the block-spring-Earth system is the same at point X as it is at point Z .
B) The spring potential energy of the block-spring-Earth system is the same at point X as it is at point Z .
C) The block-spring-Earth system does not have spring potential energy at point Y. D) The block-spring-Earth system has minimum potential energy at point Y .
Please give a detailed explanation.