1. Are the spring forces at both ends of a spring always equal in magnitude? 2. If yes, then the external forces at both ends are also the same in magnitude, aren't they? (Based on Newton's third law) If no, how to find the two different spring forces at each of the end? 3. If the external forces at both ends are indeed the same, then the net force acting on the spring is always zero, isn't it? Then, it will never accelerate?