When a single force acts on a particle, the force tends to rotate it either clockwise or anticlockwise direction. Suppose two or more forces act on the particle. It is possible to come to an equilibrium state under specific conditions.
Conditions of Equilibrium:
- If two forces act on the system, it can be in equilibrium condition when these two forces are collinear, opposite in direction and equal.
- Ifthree forces act on the system, it can be in equilibrium condition when these three forces are concurrent, resultant forces are zero, all forces form a triangleorobey Lame’s Theorem.
When all these forces are intersect at a single point on the plane.
- Resultant forces are zero:
Resultant forces along x-direction and y-direction should be zero
Or, ∑▒〖F_x=0〗 and ∑▒〖F_y=0〗
- Lame’s Theorem:
It states that each force should be proportional to the sine of angle between other two forces under equilibrium conditions.
- All forces form a triangle:
If the three or more than three forces act on the particle, then resultant force should give its value equal to zero in x direction and y direction shows the equilibrium of forces i.e.,∑▒〖F_x=0〗 and ∑▒〖F_y=0〗