Question

In an orbital motion, the angular momentum vector is

• A. along the radius vector
• B. parallel to the linear momentum
• C. in the orbital plane
• D. perpendicular to the orbital plane

Answer 1

Answer: (D)

If a body is rotating about an axis, then the sum of the moments of the linear moment of all the particles about the given axis is called the angular momentum of the body about that axis.

$J=I\omega =mrv$
Since direction of velocity is perpendicular to orbital plane and $J\propto v$, therefore in an orbital motion the angular momentum vector is perpendicular to the orbital plane.