A comet orbits the Sun in a highly elliptical orbit. Which of the following quantities remains const

Question

A comet orbits the Sun in a highly elliptical orbit. Which of the following quantities remains constant throughout its orbit?

Professor PC Thomas Classes · Answer

The gravitational force on the comet acts along the line joining it to the Sun, meaning it is a central force. Since the torque produced by a central force is zero, the angular momentum of the comet remains constant throughout its orbit. Linear speed, angular speed, and kinetic energy vary as the distance to the Sun changes.