Question

A particle of mass $m=2\text{kg}$ starts moving on a straight line $y=2$ with a constant velocity $10\hat{i}\text{m/s}$. Its angular momentum about origin $\left(\overrightarrow{L}\right)$ for the path from point $A$ to point $B$

• A. Continuously decreases
• B. Continuously increases
• C. Remains constant
• D. First increases and then decreases.

Answer 1

The correct option is C Remains constant

As we know, $\overrightarrow{L}=mv{r}_{\perp }$
While moving from $A$ to $B$, the perpendicular distance of line of velocity from the origin always remains constant (equals to $2\text{units})$.
$r_{\perp }$ = constant
Hence, $\overrightarrow{L}$ = constant
Angular momentum remains constant.