A body of mass 1 kg is placed at a distance of 2 m from another body of mass 10 kg. At what distance from the body of mass 1 kg, another body of mass 5 kg must be placed so that the net gravitational force acting on the body of mass 1 kg is zero?
We have to find distance x, so that the net force acting on 1 kg body is equal to zero.
The force applied by 10 kg body on 1 kg body will be towards 10 kg body and that applied by 5 kg body on 1 kg body will be towards 5 kg body.
These forces should be equal and opposite.
G×5×1x2=G×10×122
5x2=52⇒x2=2
⇒x=212=1.414m
The 5 kg body should be kept at 1.414 m from 1 kg body.