Mechanical Energy and Oscillations???

Question

Consider a 8.89-kg mass on the end of a linear spring in simple harmonic motion. The spring has spring constant 4.31 N/m. When the spring is maximally extended, it is 0.0156 m from the place in the oscillation where it is maximally compressed. The equilibrium position of the spring is midway between these two extremes. What is the mechanical energy of the mass in this oscillation? (Answer in J.)

Answer 1

At the points of maximum extention, all of the energy is spring potential energy. In your problem, x is half of .0156 m. You also know the spring constant k. Now you can calculate the total energy

E = 1/2 k x^2