A ball balanced on a vertical rod is an example of

A ball balanced on a vertical rod is an example of

stable equilibrium
unstable equilibrium
neutral equilibrium
perfect equilibrium
This question was previously asked in
UPSC NDA-1 – 2018
A ball balanced precisely on a vertical rod is in unstable equilibrium.
– In unstable equilibrium, if the object is slightly displaced from its equilibrium position, it will move further away from that position.
– A ball balanced on a pointed object or the crest of a curve represents a point of unstable equilibrium. Any tiny disturbance will cause it to fall.
– Stable equilibrium occurs when a slight displacement causes the object to return to its original position (e.g., a ball in the bottom of a bowl).
– Neutral equilibrium occurs when a slight displacement causes the object to remain in its new position (e.g., a ball on a flat surface).