Lami’s Theorem

In statics, Lami’s theorem is an equation that relates the magnitudes of three coplanar, concurrent and non-collinear forces, that keeps a body in static equilibrium.
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.
Consider three forces A, B, C acting on a particle or rigid body making angles α, β and γ with each other.

Lami's Theorem

According to Lami’s theorem, the particle shall be in equilibrium ifLami's Theorem condition
The angle between the force vectors is taken when all the three vectors are emerging from the particle.

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Vinodh Reddy is a Mechanical Engineer and Editor-in-chief of ME Mechanical. He holds a Bachelor of Engineering (Honours) degree in Mechanical Engineering. He also blogs at Way2Learn for Exams. He interested in the manufacturing field.

All Comments

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    chitransh gandhi Nov 27, 2015 4:46 pm Reply
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    Ibdul Jan 20, 2016 1:53 am Reply
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  • what type of force system in lami’s experiment

    omkar deshmukh Jan 10, 2018 9:45 pm Reply
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    Zibah Jan 15, 2018 7:15 pm Reply
  • Hello sir
    Sir why should we only use sine angle why can’t we use cos angle or so

    Karthik Aug 8, 2018 5:09 am Reply
    • It is derived and we get sine

      Vinodh Reddy Chennu Dec 13, 2018 8:47 am Reply
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