The stable and unstable equilibrium, along with loll, are a fundamental part of the characteristics of equilibrium in physics. Contrary to what many believe, balance is not just the absence of change in a body.
There are several types of equilibria and each one represents the definition of a specific movement under the effects of gravity and other factors.
All these types represent the way in which a body is held or not in a specific space and explain the difference between, for example, the displacement of a pendulum, a rod and a wheel.
One of them will return to its initial position, while the other will remain in its final position, and the last one will remain stable without undergoing any change.
What is balance?
To start you need to know what balance is. The word balance comes from the Latin aequilibrĭum. This word is divided into "aequus" which represents equality and "pound" which represents a scale. Hence, it is for this reason that the word balance represents a sense of stability and counterweight.
In physics, equilibrium represents the state of a body at rest where the sum of all its forces counteract each other.
Since balance offers us a sense of stability, it is common to think that there is only one way to define it, but we could not be more wrong.
This phenomenon can occur both in a static body, one that is not subject to change, and a body in motion. This last example of equilibrium can be generated in 3 types: stable, unstable and indifferent.
Stable equilibrium
The balance of a body is stable when, when it is removed from its initial position, it returns to it due to the effect of gravity exerted on the body.
A clear example of this type of equilibrium would be an object such as the pendulum, which despite being removed from its position, returns by itself to its starting point.
We can also take a book on a table as an example; lifting and releasing it will drop it back to its initial position.
Unstable balance
The unstable balance of a body occurs when said body, when removed from its initial position, is kept away from it by the effect of gravity. This happens because the center of gravity is higher than the suspension point.
We can see this type of balance when we place a pencil standing on the tip and when it is released it will fall on the table. Said object will not return to its initial position. We can also see him with a cane, which when released, will fall to the floor without going back up.
Indifferent balance
Indifferent equilibrium exists when, despite the fact that a body is moved, it remains in balance in any position.
This happens because its center of gravity is in the middle of the body with respect to the center of suspension. A clear example of this type of balance would be a wheel on its axis.
References
- Stable and Unstable Equilibrium. Retrieved on December 7, 2017, from Owlcation: owlcation.com.
- Stable Equilibrium. Retrieved on December 7, 2017, from Merriam Webster: merriam-webster.com
- Stable Equilibrium. Retrieved on December 8, 2017, from Encyclopædia Britannica: britannica.com.
- States of Equilibrium. Retrieved on December 8, 2017, from City Collegiate: citycollegiate.com
- Unstable Equilibrium. Retrieved on December 7, 2017, from The Free Dictionary: merriam-webster.com
- Unstable Equilibrium. Retrieved on December 8, 2017, from Edu Media: edumedia-sciences.com.