A person places a bathroom scale in the center of the floor and stands on the scale with...

A person places a bathroom scale in the center of the floor and stands on the scale with his arms at his sides ( Fig. 3.26a). If he keeps his arms rigid and quickly raises them over his head (Fig. 3.26b), he notices the scale reading increases as he brings his arms upward. Why? Then, with his arms over his head (Fig. 3.26c), he quickly lowers his arms to his side. How does the scale reading change and why? (Try it yourself.)