19. In the right figure, what magnitude of the forceapplied horizontally at the axle of the wheel is necessary to raise the wheel over an obstacle of height h? The wheel's radius is r and its mass is m.
(A)\( \frac{\sqrt{2rh-h^2}}{r+h}mg \)
(B)\( \frac{\sqrt{2rh-h^2}}{r-h}mg \)
(C)\( \frac{\sqrt{2rh+h^2}}{r-h}mg \)
(D)\( \frac{2\sqrt{2rh-h^2}}{r-h}mg \)
(E)\( \frac{\sqrt{2rh+h^2}}{r+h}mg \)

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