Write an equation for each of the following relationships. Use k as the constant of variation.
1.) Q varies jointly as s and r.
2.) C varies jointly with u and the cube of v.
3.) R varies jointly with m and the square root of h.
4.) The volume of a cone (V) varies jointly with its height h and the square of the radius r of its base.
5.) The work (w) done by a force moving an object varies jointly with the mass (m) of the object and the distance (d) that it is moved.