Conditions of Equilibrium

Q. What are the conditions of Equilibrium?

There are two conditions for a body to remain in the state of Equilibrium.

First Condition of Equilibrium:

Sum of all the forces acting on a body must be zero.

ΣF = 0

Second Condition of Equilibrium:

Sum of all the torques acting on body must be zero.

Στ = 0

Thus, for a body to attain the state of equilibrium all the force acting on that body and all the torques applied on that body must equal to zero. Which means same amount of force and torques must be applied which cancels each other and puts the body in state of equilibrium

Examples:

1. A boy is standing between two other boys and those two boys are pulling him in opposite directions but the force they are using to pull him is same, therefore the boy does not change its position and that puts him into the state of equilibrium.
2. A door is pushed from one side and at the same time the door is pushed from the other with same force that produces same amount or torque on both sides thus the door does not rotate and stays in equilibrium.