Question

A particle of mass $5kg$ is moving with a uniform speed $3\sqrt{2}$ in $XOY$ plane along the line $Y=X+4$. The magnitude of its angular momentum about the origin is

• A. $40$ units
• B. $60$ units
• C. $Zero$
• D. $40\sqrt{2}$ units

Answer 1

The correct option is B $60$ units

$y=x+4$ given.
$x-y+4=0$
Perpendicular distance from origin$r=\frac{4}{\sqrt{2}}=2\sqrt{2}$
Now angular momentum$=mvr$
$=5\times 3\sqrt{2}\times 2\sqrt{2}$
$=60$