A 5.0 kg mass attached to a spring is displaced 8 cm from equilibrium position. It is released and it oscillates with a frequency f. When the block is 2 cm from equilibrium, it has speed of 3 m/s. What is the frequency of the oscillation? Assum the surface is frictionless. I know the answer is 6.2 Hz but i need to know how they got to this answer.