Question

State Lami’s theorem.
State the necessary condition for application of Lami’s theorem.

Answer 1

Lami's theorem states that if three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two forces.

According to Lami’s theorem, the particle shall be in equilibrium if : 
${\displaystyle \frac{A}{\sin \alpha }=\frac{B}{\sin \beta }=\frac{C}{\sin Y}}$
The conditions of Lami’s theorem are : 
(1)Exact 3 forces must be acting on the body.
(2)All the forces should be either converging or diverging from the body.