a. A point is equally likely to fall anywhere on the semi-circle defined by the equations, x^2+y^2=1, y>=0. Find the pdf of the y-component of the point's position.
b. A point is equally likely to be found anywhere on the surface of the hemisphere described by x^2+y^2+z^2=1, z>=0. Find the pdf of the z-component of the point's position.