Question

What is gravitational potential energy of system consisting of two concentric spherical shells of mass, $m$ , and $4m$ and radii $R$ and $2R$ .

• A. $\frac{- 2 G m^{2}}{R}$
• B. $\frac{- 9 G m^{2}}{2 R}$
• C. $−\frac{5 G m^{2}}{2 R}$
• D. $−\frac{13 G m^{2}}{2 R}$

Answer 1

Answer: (D)

Total energy equals sum of self energy of two shells and their mutual energy.