1. The problem statement, all variables and given/known data It was stated that the block separates from the compressed spring when the spring reached its equilibrium length of x=0. Explain why separation doesn't take place before (or after) this point. I understand how this works, intuitively. What I don't understand is my textbook's answer guide. "Until the x = 0 point, the spring has a positive acceleration and is accelerating the block, and therefore will remain in contact with it. After the x = 0 point, the spring begins to slow down, but (in the absence of friction), the block will continue to move with its maximum speed and will therefore move faster than the spring and will separate from it." 2. Relevant equations N/A 3. The attempt at a solution How can the spring begin to slow down after x=0? At x=0, the spring is at its natural uncompressed/unstretched length. If it begins to slow down after x=0, that means that it stretches beyond its original length, but this can't be true.