According to Kepler's second law, the areal velocity of a planet revolving around the Sun is constan

Question

According to Kepler's second law, the areal velocity of a planet revolving around the Sun is constant. This is a direct consequence of the conservation of which of the following?

Professor PC Thomas Classes · Answer

The areal velocity of a planet is given by $\frac{dA}{dt} = \frac{L}{2m}$. Since the gravitational force is a central force, the torque is zero, making the angular momentum $L$ constant.