If I have spring system following Hooke's Law I' -K The k is constant. So it doesn't change. Let us say that I initially stretch the spring by 10 cm from its point of equilibrium. The spring is now 10 cm to the right of the equilibrium point. Now, let us say that I compress the spring by 10 cm from its point of equilibrium. The spring is now 10 cm to the left of the equilibrium point. The question is this: In which of these two points (stretched or compressed) is the amount of restoring force the largest? The restoring force is largest when stretched The restoring force is largest when compressed It's the same amount of force in both, but they are pointing in opposite directions.