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RRB JE ME CBT 2 Previous Paper 2: Held on 31 Aug 2019

Option 4 : Lami's theorem

RRB JE ME 2019 CBT 2 Full Mock Test

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150 Questions
150 Marks
120 Mins

**Explanation:**

Lami's theorem is an equation relating the magnitudes of three coplanar, concurrent and non-collinear forces, which keeps an object in static equilibrium, with the angles directly opposite to the corresponding forces. According to the theorem:

\(\frac{A}{{\sin \alpha }} = \frac{B}{{\sin\beta }} = \frac{C}{{\sin\gamma }}\)

__Important Points__

Varignon’s Principle of moments (or the law of moments):

It states, “If a number of coplanar forces are acting simultaneously on a particle, the algebraic sum of the moments of all the forces about any point is equal to the moment of their resultant force about the same point.”

i.e. R × r = F1 × r1 + F2 × r2