JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2022
- Easy
- MCQ
The torque of a force \(5 \hat{i}+3 \hat{j}-7 \hat{k}\) about the origin is \(\tau\). If the force acts on a particle whose position vector is \(2 \hat{i}+2 \hat{j}+\hat{k}\), then the value of \(\tau\) will be.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(-17 \hat{i}+19 \hat{j}-4 \hat{k}\)
Step-by-step Solution
Detailed explanation
\(\vec{\tau}=\vec{r} \times \vec{F}=\left|\begin{array}{ccc}i & j & k \\ 2 & 2 & 1 \\ 5 & 3 & -7\end{array}\right|\)
\(=i(-14-3)-j(-14-5)+\hat{k}(6-10)\)
\(=-17 \hat{i}+19 \hat{j}-4 \hat{k}\)
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