Drag [b]A[/b] and [b]B[/b] to set the limits of the path from A to B.[br]Use the [b]xFromAtoB slider[/b] to move the end of the spring.[br]Check [b]Start[/b] to animate the path from A to B.[br][br]Check [b]showHand[/b] to show the force and work done by a hand[br]controlling the spring [i][by keeping the netForce equal to zero][/i].[br][br]The equilibrium position is at x=0 (suggested by the grey spring).