According to Kepler's 2nd Law of planetary motion, a planet moves fastest in its orbit when it is
A) undergoing retrograde motion
B) in between perihelion and aphelion
C) at perihelion
D) at aphelion

Question

Quizplus · Accepted Answer

Kepler's 2nd Law, also known as the Law of Equal Areas, states that a planet sweeps out equal areas in equal times. This means that when a planet is closer to the Sun, at perihelion, it moves faster in its orbit in order to cover the same amount of area in the same amount of time as it would at a farther distance from the Sun, at aphelion. Therefore, the correct choice is C) at perihelion.

According to Kepler's 2nd Law of Planetary Motion, a Planet