A planet of constant mass orbits the sun in an elliptical orbit. Neglecting any friction effects, what happens to the planet's rotational kinetic energy about the sun's center?
A) It increases continually.
B) It increases when the planet approaches the sun, and decreases when it moves farther away.
C) It remains constant.
D) It decreases when the planet approaches the sun, and increases when it moves farther away.
E) It decreases continually.

Question

Quizplus · Accepted Answer

The rotational kinetic energy of a planet orbiting the sun in an elliptical orbit changes due to its varying distance from the sun. When the planet is closer to the sun, its speed increases due to the stronger gravitational pull, leading to an increase in kinetic energy. Conversely, as the planet moves farther away, its speed decreases, resulting in a decrease in kinetic energy. This is in accordance with Kepler's second law, which states that a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time, implying that the planet moves faster when it is closer to the sun.

A Planet of Constant Mass Orbits the Sun in an Elliptical