Question

Lami's theorem is applicable to

• A. Two concurrent forces
• B. Three non-coplanar forces
• C. Three concurrent forces in equilibrium
• D. Any number of forces

Hint:

Lami's theorem is used only when three concurrent forces keep a body in equilibrium.

Answer 1

The Correct Option is C

Concept:
Lami's theorem is used in engineering mechanics for a body in equilibrium under three forces.

Step 1: The three forces must act at one common point.

Step 2: Such forces are called concurrent forces.

Step 3: The body should be in equilibrium, meaning the resultant force is zero.

Step 4: Lami's theorem relates each force to the sine of the angle between the other two forces. \[ \frac{F_1}{\sin\alpha}=\frac{F_2}{\sin\beta}=\frac{F_3}{\sin\gamma} \]

Step 5: Therefore, Lami's theorem is applicable to three concurrent forces in equilibrium. \[ \boxed{\text{Three concurrent forces in equilibrium}} \]