A 500g particle has velocity vx = -5.0m/s at t = -2s. Force Fx = (4-t^2)N is exerted on the particle between t = -2s and t = 2s. This force increases from 0N at t = -2s to 4 N at t = 0 and then back to 0 N at t = 2s. What is the particle's velocity at t = 2s?