According to what we now know from Newton's laws, which of the following best explains why Kepler's second law is true?
A) A planet's total orbital energy must be conserved as it moves around its orbit.
B) Orbits must be elliptical in shape.
C) Gravity is an inverse cube law.
D) This effect happens because of the influence of other planets on a particular planet's orbit.

Question

Quizplus · Accepted Answer

Kepler's second law, which states that a planet moves faster in its orbit when it is closer to the Sun, can be explained by the conservation of the planet's total orbital energy, according to Newton's laws. As a planet gets closer to the Sun, its gravitational potential energy decreases, but its kinetic energy increases by an equal amount, keeping the total energy constant. This conservation of energy requires the planet to move faster when it is closer to the Sun and slower when it is farther away.

According to What We Now Know from Newton's Laws, Which