Two bodies of masses m and 4 m are placed at a distance r. The gravitational potential at a point on the line joining them where the gravitational field is zero is :
Given:
Two masses m and 4m kept at a distance r
Let gravitetional potential is zero at a point p
Gmx2−G(4m)(r−x)2=0
1x=2(r−x)
r−x=2x
3x=r
x=r/3
Potential at point p
V=−4Gmm(2r/3)−Gmm(r/3)
V=−Gm(6r+3r)=−9Gmr