In Problems 1-3, use spherical coordinates to find the indicated quantity.
1. Mass of the solid inside the sphere ( = b and outside the sphere ( = ( (a < b) if the density is proportional to the distance from the origin
2. Mass of a solid inside a sphere of radius 2( and outside a circular cylinder of radius ( whose axis is a diameter of the sphere, if the density is proportional to the square of the distance from the center of the sphere
3. Center of mass of a solid hemisphere of radius a, if the density is proportional to the distance from the center of the sphere