Q 11-06-015NEETNEET 2020Top questionEasy
Find the torque about the origin when a force of $3\hat{j}$ N acts on a particle whose position vector is $2\hat{k}$ m.
Answer: (C) $-6\hat{i}$ N m
$$\vec{\tau} = \vec{r} \times \vec{F} = 2\hat{k} \times 3\hat{j} = 6(\hat{k} \times \hat{j}) = -6\hat{i}\ \text{N m}$$
Solution by Sreeraj P, M.Sc Physics