Question

When there is no external torque acting on a body moving in elliptical path, which of the following quantities remain constant:

• A. kinetic energy
• B. potential energy
• C. linear momentum
• D. angular momentum

Answer 1

The correct option is D angular momentum

Torque $\tau =\frac{dL}{dt}$

where $L$ is the angular momentum.

If there is no external torque, $\tau =0$

$⟹L$ is conserved.