Answer
(a) The kinetic energy is maximum at $y=0$.
(b) The gravitational potential energy is maximum at $y=+A$
(c) The elastic potential energy is maximum at $y = -A$
(d) The total potential energy is minimum at $y = 0$
Work Step by Step
(a) The speed is maximum at the equilibrium point $y= 0$. Thus the kinetic energy is maximum at $y=0$
(b) The gravitational potential energy is maximum at the highest point which is at $y=+A$
(c) The elastic potential energy is maximum when the spring is at its maximum stretch distance which is at $y = -A$
(d) The total energy in the system is constant. Thus the total potential energy is minimum when the kinetic energy is maximum which is at $y = 0$
