Bomb the force of the spring is the force at both ends at the same time, the size of the phase the same direction is opposite, that is, the same as pull or the same as pressure.

When the object at one end of the spring is fixed in the air, the spring stress is MG. After the release, the object and the spring begin to fall, and the spring stress begins to decrease slowly, straight to zero, but not always zero, due to inertia, the two objects will continue to be relative. Movement, spring force begins to increase plus, after reaching a certain amount, it starts to decrease. The principle is the reciprocating shock of the spring......