In lab, you attach one end of an ideal spring (of negligible mass) to a wall and the other end of the spring to a 0.200kg pascar that sits at rest on a frictionless, horizontal track. you then pull the pascar horizontally and let go, causing it start it oscillating. the elapsed time from when the pascar first moves through the equilibrium point to the second time it moves through the equilibrium point is 2.60s. find the spring constant, k, of the spring.