An electric field at a given position is 2 LaTeX: \hat{\bf{i}}i ^ 10 LaTeX: \hat{\bf{j}}j ^V/m. The magnitude of the electrostatic force on an object with charge 6 C is equal to N.

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?