Spring damping

void OnCollisionStay(Collision col) {
    usedforce = Mathf.Clamp(force - force * rangechange * damping, 100, force * 2);

    direction = tform.position - targetPos.position;
    player.AddForceAtPosition(direction * usedforce, targetPos.position);
}
void FixedUpdate () {
    range = (tform.position - targetPos.position).magnitude;
    rangechange = oldrange - range;
    oldrange = range;

    body.AddForce((targetPos.position - tform.position) * speed, ForceMode.Acceleration);
}