public void update (double elapsedTime, Dimension bounds, List<Force> activeForces) {
        for (Force f : activeForces) {
            f.applyForce(elapsedTime, bounds, myMasses);
        }
        for (Spring s : mySprings) {
            s.update(elapsedTime, bounds);
        }
        for (Mass m : myMasses) {
            m.update(elapsedTime, bounds);
        }
    }