Find the proper potential energy of gravitational interaction of matter forming
(a) a thin uniform spherical layer of mass m and radius R,
(b) a uniform sphere of mass m and radius R(make use of the answer to Problem)
A. `- (GM^(2))/(R)`
B. `-(1)/2(GM^(2))/(R)`
C. `-(3)/5(GM^(2))/(R)`
D. `-(2)/3(GM^(2))/(R)`