a spring of length 100 cm placed horizontally. One end of the spring is attached to a stable surface and the other end is attached to a mass of 400 g. Assume the system isolated with no friction. The spring constant is k = 200 N/m. (a) If the mass is pulled 20 cm away from its equilibrium position, what is the force applied to the mass in that position? (b) If the mass is released 20 cm away from its equilibrium position, what would be the mechanical energy of the system? (c) Calculate the maximum speed that the mass can reach. Where would the mass be when it reaches maximum speed? Justify your answers. (d) Calculate what length a pendulum with the same mass would need to be to have the same oscillation period as this mass-spring system. Assume no friction in both cases.