Question

The angle between the linear momentum and angular momentum of a particle moving along a circle is

• A. $0^{\circ }$
• B. $45^{\circ }$
• C. $90^{\circ }$
• D. $180^{\circ }$

Answer 1

Answer: (C)

The angular momentum of a particle moving along a circle of radius $r$ is
$\vec{L}=\vec{r}\times \vec{p}$ where $\vec{p}$ is the linear momentum of the particle
By the definition of vector product, $\vec{L}$ is perpendicular to $\vec{p}$.
So the angle between them is $90^{\circ }$.