System and energy conservation

A block of mass m on a level, frictionless surface is attached to an ideal massless spring of constant k, as shown below. At time t,, the spring is stretched, and the block is released from rest at m : m1, At time tf, the spril is neither stretched nor compressed, and the block reaches .16 : 0 moving to the left with speed 11f. Just hcfmc Consider the above from the perspective of two different choices of system: - system B, which consists of the block alone, and - system SB, which consists of the spring and the block. Two students have a discussion about the above demonstration. i. the two students are considering the work done on the two systems: Student 1: \"I think that the spring does positive work on the block, and the wall does positive work on the spring-block system." Student 2: "But the point where the wall exerts a force on the spring-block system doesn't move, so how can the wall do work? The displacement is zero.\" With which student, if either, do you agree? What displacement should be used to calculate the work done on system SB by the wall? Explain your conclusions, ii. the two students are considering an energy analysis of system B (the block alone): Student 1: "The spring does work on system B, so system B's spring potenh'al energy changes.\" Student 2: \"I agree that the spring does work on system B, but there aren't any springs in system B, so how could it have spring potential energy? It's just a block." With which student, if either, do you agree? Explain