You are trying to raise a bicycle wheel of mass m and radius r up over a curb of height h. to do this, you apply a horizontal force f s (fig. p11.72). what is the smallest magnitude of the force f s that will succeed in raising the wheel onto the curb when the force is applied (a) at the center of the wheel and (b) at the top of the wheel? (c) in which case is less force required?