Equilibrium for Coplanar Forces | Condition of Equilibrium Coplanar Forces:
Forces in equilibrium mean that they are balanced.
Coplanar forces act in the same plane. Two balanced forces are equal in magnitude but opposite in direction to the other.
We can see easily from the free body diagram that the resultant force is zero.
If we are considering three co planar forces in equilibrium, use the triangle of forces rule:
If 3 forces acting at a point can be represented in size or direction by the sides of a closed triangle, then the forces are in equilibrium, provided their directions can form a closed triangle.
This means that the forces can follow each other round a triangle
Notice how:
- The forces form into a closed triangle.
- The directions of the forces go round the triangle.
In statics, remember that all forces add up to zero. That does not mean that there are no forces; the forces balance each other out.
In statics problems, we need to know how to resolve forces, which can be done by:
- accurate drawing;
- use of trigonometry.
