STABLE EQUILIBRIUM
If object is in stable equilibrium and if we displace object to a very little displacement dr then it will return back to starting position.
UNSTABLE EQUILIBRIUM
If the object is in unstable equilibrium and if we displace the object to a very little displacement dr then it will not return back to its starting position.
NEUTRAL EQUILIBRIUM
In neutral equilibrium, if we displace object to a very little displacement then it will gone on its new point.