Q 11-06-040NEETJEE MainEasy
A force $\vec{F} = (3\hat{i} + 4\hat{j})$ N acts at the point $\vec{r} = (2\hat{i} - \hat{j})$ m. The torque about the origin is
Answer: (B) $11\hat{k}$ N m
$$\vec{\tau} = \vec{r}\times\vec{F} = (r_xF_y - r_yF_x)\,\hat{k} = \big(2 \times 4 - (-1) \times 3\big)\hat{k} = 11\hat{k}\ \text{N m}$$
Solution by Sreeraj P, M.Sc Physics