For a solid , What is the total energy of an oscillator ?

What is the total energy for one mole solid substance ?

Why is heat energy needed to melt a solid ? What is this heat energy called ?

A simple harmonic oscillator has amplitude 'A'. If the kinetic energy of oscillator is one-fourth of the total energy, then the displacement is

A simple harmonic oscillator has amplitude 'A'. If the kinetic energy of oscillator is one-fourth of the total energy, then the displacement is