Question

A particle of mass $m$ is moving with constant velocity $v$ parallel to the x-axis in $x-y$ plane as shown in the figure. Calculate its angular momentum with respect to the origin at any time $t$.

Answer 1

$\overrightarrow{L}=\overrightarrow{r}\times \overrightarrow{b}=m(\overrightarrow{r}\times \overrightarrow{v})$

Here $\overrightarrow{r}$ is the perpendicular distance of the point from origin

The velocity remains constant with time.

Therefore, its angular momentum is constant.