In Lab 9 (Hooke's Law and Conservation of Energy), you learned that when a spring is stretched or compressed, it also stores energy, according to the equation U = (1/2) kx2 What is the conservative force corresponding to this potential energy function? In Lab 9 (Hooke's Law and Conservation of Energy), you learned that when a spring is stretched or compressed, it also stores energy, according to the equation U = (1/2) kx2 What is the conservative force corresponding to this potential energy function? F = kx F = -kx F = (1/2)kx F = -(1/2)kx F = -mg