A bead under the influence of gravity slides down a frictionless wire whose height is given by the function y(x). At position (x, y) = (0, 0) the wire is vertical and the bead passes this point with a speed v0. What should the shape of the wire be [i.e. what is y(x)] so that the vertical speed remains constant as v0 at all future times? Assume the curve heads toward positive x. Hint: consider energy conservation.