Question

As a planet orbits the Sun identify which of the following quantity most remain constant?

• A. velocity
• B. gravitational force
• C. radius of orbit
• D. angular momentum
• E. the product of mass and velocity

Answer 1

Answer: (D)

angular momentum

Since no external torque on the planet due to gravitational force exerted by Sun, we have $\tau =\frac{dL}{dt}$

Hence the angular momentum $L=constant.$