Systems of coplanar forces (statics) — A/L Combined Mathematics

How do I practise Systems of coplanar forces (statics)?

1 question with a worked solution

1. According to Lami's Theorem for three coplanar concurrent forces P, Q, and R in static equilibrium, what is the relation connecting the forces to the angles α, β, and γ between the other two forces?
   1. A) P / cos α = Q / cos β = R / cos γ
   2. B) P / sin α = Q / sin β = R / sin γ
   3. C) P sin α + Q sin β + R sin γ = 0
   4. D) P · α = Q · β = R · γ
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   Correct answer: B) P / sin α = Q / sin β = R / sin γ

   Lami's theorem states that if three coplanar forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two forces: P / sin α = Q / sin β = R / sin γ.

   Show worked solution

   Step 1: State Lami's theorem: P / sin α = Q / sin β = R / sin γ. Answer: P / sin α = Q / sin β = R / sin γ.
   Modelled on: the A/L Combined Mathematics examination pattern

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Where does Systems of coplanar forces (statics) fit in the syllabus?

Year 2 · Term 2