I have read posts about this but still don't have a good handle on it. I am confused about something that I know is simple. If a mass is attached to a spring, the spring will stretch according to Hooke,s law, correct? So won't the weight, (mg) balance out the spring force of -kx? So in other words, won't x=mg/k? My confusion is when I look at the same problem using a potential energy balance. the balance of the change in spring potential energy of 1/2kx^2 with the change in potential energy of the hanging mass mgx will result in x=2mg/k. So the energy equation shows twice as much stretch as the force equation. Can someone please clear this up for me?