Two heavy sphere each of mass `100 kg` and radius `0.10 m` are placed `1.0 m` apart on a horizontal table. What is the gravitational field and potential at the mid point of the line joining the centres of the sphere? Is an object placed at that point in equilibrium? If so, is the equilbrium stable or unstable.

Explanation

Gravitational field at the mid point of the joining their centres is given by
`vecE=(GM)/((r//2)^(2))=(-vecr)+(GM)/((r//2)^(2))(vecr)=bar0`
Gravitational potential at the mid point of the line joining their cenres is given by
`V=(-GM)/((r//2))+(-GM)/((r//2))=(-4GM)/r`
`=(4xx6.67xx10^(-11)xx100)/1`
`=-2.7xx10^(-8)J//kg`