A mass attached to a spring is pulled a distance A from the equilibrium position and released from rest. It then undergoes SHM. When the mass is A/2 from equilibrium, how is the energy divided between potential and kinetic?

1. The energy is 25% spring potential energy and 75% kinetic energy
2. The energy is 50% spring potential energy and 50% kinetic energy
3. The energy is 75% spring potential energy and 25% kinetic energy
4. One of the above, but it depends whether the object is moving toward or away from the equilibrium position
5. None of the above

The total energy is ½ kA². At x = A/2 the spring potential energy is ½ kx² = kA²/8, which is 25% of the total energy.