A 6.0-kg mass at the end of a spring vibrates 3.0 times per second with an amplitude of 0.13m. Determine (a) the velocity when it passes the equilibrium point. (b) the velocity when it is 0.10m from equilibrium. (c) the total energy of the system and (d) the equation describing the motion of the mass, assuming that x was a maximum at t=0.