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MHT CET 2025 (22 Apr, Shift 1) · Torque, Couple & Equilibrium of Rigid Bodies

Torque, Couple & Equilibrium of Rigid Bodies question from MHT CET 2025 (22 Apr, Shift 1)

Q4MHT CET 2025 · 22 APR · SHIFT 1Easy

Torque, Couple & Equilibrium of Rigid Bodies

If force F⃗=−3i^+j^+5k^\vec{F} = -3\hat{i}+\hat{j}+5\hat{k} acts along r⃗=7i^+3j^+k^\vec{r} = 7\hat{i}+3\hat{j}+\hat{k} then the torque acting at that point is

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Answer: (a)

  1. Torque τ⃗=r⃗×F⃗\vec{\tau} = \vec{r}\times\vec{F} with r⃗=(7,3,1)\vec{r} = (7,3,1), F⃗=(−3,1,5)\vec{F} = (-3,1,5).
  2. τx=3(5)−1(1)=14\tau_x = 3(5)-1(1) = 14, τy=−[7(5)−1(−3)]=−38\tau_y = -[7(5)-1(-3)] = -38, τz=7(1)−3(−3)=16\tau_z = 7(1)-3(-3) = 16
  3. So the answer is (a) 14i^−38j^+16k^14\hat{i}-38\hat{j}+16\hat{k}.
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