An object with mass $0\mathrm{.}230$ kgkg is acted on by an elastic restoring force with force constant $10\mathrm{.}4$ N$/$mN$/$m$.$ The object is set into oscillation with an initial potential energy of $0\mathrm{.}150$ JJ and an initial kinetic energy of $6\mathrm{.}6010-2$ J$.$

What is the amplitude of oscillation?

What is the potential energy when the displacement is one$-$half the amplitude?

At what displacement are the kinetic and potential energies equal?

What is the value of the phase angle $$ if the initial velocity is positive and the initial displacement is negative?