The equilibrant force is a single force that balances the resultant force, bringing an object into a state of equilibrium.
Understanding Resultant and Equilibrant Forces
In physics, when multiple forces act on an object, their combined effect can be represented by a single force known as the resultant force.
- Resultant Force: According to the definition, the resultant force is defined as a single force that is working on an object, product of the sum of all the forces working on the object. It represents the net effect of all forces acting on the object. If the resultant force is zero, the object is in equilibrium (either at rest or moving at a constant velocity).
- Equilibrant Force: The reference states that the equilibrant force consists of a force that is equal in magnitude to the resultant force but opposite in direction. Its purpose is to counteract the resultant force. When the equilibrant force is applied along with the other forces, the net force on the object becomes zero, achieving equilibrium.
The Core Relationship: Equal Magnitude, Opposite Direction
The fundamental relationship between the resultant force and the equilibrant force lies in their magnitude and direction:
- Magnitude: The equilibrant force has the exact same magnitude as the resultant force. If the resultant force is 10 Newtons (N), the equilibrant force is also 10 N.
- Direction: The equilibrant force acts in the completely opposite direction to the resultant force. If the resultant force points North, the equilibrant force points South.
Think of it this way: If the resultant force is pushing an object with a certain strength in one direction, the equilibrant force is pulling or pushing with the same strength in the exact opposite direction.
Comparing Resultant and Equilibrant Forces
Here's a simple comparison:
| Feature | Resultant Force | Equilibrant Force |
|---|---|---|
| Definition | Sum of all forces on an object | Force that balances the resultant force |
| Magnitude | Represents the net force magnitude | Equal to the magnitude of the resultant force |
| Direction | Represents the net force direction | Opposite to the direction of the resultant force |
| Effect | Causes acceleration (if non-zero) | Counteracts resultant to achieve equilibrium |
Practical Example
Imagine a heavy box being pulled by two people. The combined pull of these two people can be represented by a single resultant force pointing forward. To prevent the box from moving (i.e., to achieve equilibrium), a third person could push the box backward with a force equal in strength to the resultant force and in the opposite direction. This force applied by the third person is the equilibrant force.
In essence, the equilibrant force is the force required to cancel out the resultant force and bring the system into a state of equilibrium where the net force is zero.
