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

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

.

$6 \hat{j} N m$
$- 6 \hat{i} N m$
$6 \hat{k} N m$
$6 \hat{i} N m$

Solution

$\vec{F} = 3 \hat{j} N, \vec{r} = 2 \hat{k}$

$\vec{τ} = \vec{r} \times \vec{F} = 2 \hat{k} \times 3 \hat{j} = 6 (\hat{k} \times \hat{j})$

$= 6 (- \hat{i})$

$\vec{τ} = - 6 \hat{i} N m$

Asked in: NEET 2020 (Phase 1)

Practice more Rotational Motion questions on Aicharya