At that point it is no longer trying to uncompress nor is it trying to stretch. This is the same thing as a pendulum at the bottom of its swing, no longer falling but not yet rising against gravity. Thus the kinetic energy there is the same as the potential energy when it is compressed. The energy of compression is
This gives E=0.5(37)(0.2)²=0.74J
This is the same as the kinetic energy when it is at natural length
This gives E=0.5(37)(0.2)²=0.74J
This is the same as the kinetic energy when it is at natural length