1. The problem statement, all variables and given/known data A spring of negligible mass stretches 3.00 cm from its relaxed length when a force of 7.50 N is applied. A 0.500-kg particle rests on a frictionless horizontal surface and is attached to the free end of the spring. The particle is pulled horizontally so that it stretches the spring 5.00 cm and is then released from rest at t=0. Determine the displacement x of the particle from the equilibrium position at t=0.500s. 2. Relevant equations Not sure 3. The attempt at a solution I've calculated the spring constant, the average acceleration from the stretched position to the equilibrium solution but I can't do anything to solve for time.. Can anyone tell me how to solve this question?