Blocks A (0.1 kg) and B (0.4 kg) ride on a frictionless level surface in one dimension and have Velcro on their sides, so that they stick when they touch. Block B is also connected to a massless, ideal spring (k = 50 N/m) which extends horizontally and is connected to a wall. Initially Block B is at rest, and block A approaches from the left (see figure).
Immediately after the hit, the two blocks are going 0.2 m/s. They then oscillate. Consider the following three statements in questions 19 and 20.
I. Momentum is conserved.
II. Kinetic energy is conserved.
III. The sum of kinetic and spring potential energy is conserved.
Which of the statements is true during the oscillation?