1. The problem statement, all variables and given/known data A 1.2 kg glider moving at 3.0 m/s right undergoes an elastic head-on collision with a glider of equal mass moving at 3.0 m/s left . The collision is cushioned by a spring with k=6.0*10^4 N/m. Determine the compression in the spring when the second glider is moving at 1.5m/s. Ans =1.6cm 2. Relevant equations same mass therefore.. vf1= Vi2 vf2= Vi1 3. The attempt at a solution I think I would be able to do this question if could understand it. Is the initial velocity of the second glider 3m/s or 1.5m/s?. I would really appreciate if someone can explain this question to me because I really don't know where to start.