A body of mass 4 kg is attached to a coil spring and oscillates vertically with SHM. The amplitude of the oscillations is 0.5 m, and at its highest point of the motion, the spring has its natural unstretched length. Calculate the elastic potential energy of the spring, the kinetic energy of the body, and its gravitational potential energy relative to the lowest point of the motion, and the sum of these 3 energies, when the body is (a) at its lowest point, (b) at its equilibrium position, (c) at its highest point