It is found that a particular spring that does not follow Hooke's law exerts a restoring force of the form F(x) = -αx - βx2 during its expansion or compression, where α = 60.0 N/m and β = 18.0 N/m2. The mass of the spring is negligible. Calculate numerically the position and velocity of the body as a function of time and find the size of the speed of the object when it is first at a distance of 0.50 m to the right of the equilibrium position x = 0.