A particle is executing simple harmonic motion with frequency f. The frequency at which its kinetic energy change into potential energy is
f/2
f
2 f
4 f
KE=12mv2=12mωAcosωt2 =12mω2A2cos2ωt =12mω2A21+cos2ωt2 =14mω2A2+14mω2A2cos2ωt
In S.H.M., frequency of K.E. and P.E. = 2 × (Frequency of oscillating particle)