What is Mechanical Equilibrium?
Mechanical equilibrium describes a state where an object experiences no net force and no net torque, meaning it is either at rest or moving with constant velocity. Within this state, there are three distinct types based on how an object responds to a small displacement: stable, unstable, and neutral equilibrium.
Stable Equilibrium: Returning to Balance
In stable equilibrium, if an object is slightly displaced from its position, it tends to return to its original state. This occurs when the object's center of gravity is at its lowest possible point, and any displacement raises it. A common example is a ball resting at the bottom of a bowl; if you push it slightly, it rolls back to the bottom.
Unstable Equilibrium: Losing Balance Easily
Unstable equilibrium is characterized by an object moving further away from its initial position after a slight displacement. Here, the object's center of gravity is at its highest possible point, and any disturbance causes it to lower. Imagine balancing a pencil on its sharpened tip; the slightest nudge will cause it to fall over.
Neutral Equilibrium: Finding a New Balance
Neutral equilibrium occurs when an object, after being displaced, remains in a new equilibrium position. In this state, a small displacement neither raises nor lowers the object's center of gravity. A ball on a flat, level surface is a perfect example: if you roll it, it stops at a new position, remaining in equilibrium there.