Question

Two small and heavy spheres, each of mass M, are placed a distance r apart on a horizontal surface. The gravitational potential at the mid-point on the line joining the center of the spheres is :

• A. Zero
• B. $-\frac{GM}{r}$
• C. $-\frac{2GM}{r}$
• D. $-\frac{4GM}{r}$

Answer 1

The correct option is D $-\frac{4GM}{r}$

V=-GM/r

so potential due to both large and small spheres

sphere at the center of them will be

V = $V_1+V_2$

=2$V_1$

=2$(-\frac{GM}{\frac{r}{2}})$

= $-\frac{4GM}{r}$