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Find the torque about the origin when a force of 3ĵ N acts on a particle whose position vector is 2k̂ m.

1. 6ĵ Nm
2. -6ĵ Nm
3. 6k̂ Nm
4. 6î Nm

Correct answer: 6î Nm

Solution

Torque is given by \( \vec{\tau} = \vec{r} \times \vec{F} \). Here, \( \vec{r} = 2\hat{k} \) and \( \vec{F} = 3\hat{j} \). Using the cross product, \( \vec{\tau} = (2\hat{k}) \times (3\hat{j}) = 6\hat{i} \).

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