The figure below shows a planet traveling in a clockwise direction on an elliptical path around a star located at one focus of the ellipse.When the planet is at point A,
A)its speed is constant.
B)its speed is increasing.
C)its speed is decreasing.
D)its speed is a maximum.
E)its speed is a minimum.

Question

The figure below shows a planet traveling in a clockwise direction on an elliptical path around a star located at one focus of the ellipse.When the planet is at point A, 
A)its speed is constant. 
B)its speed is increasing. 
C)its speed is decreasing. 
D)its speed is a maximum. 
E)its speed is a minimum.

Quizplus · Accepted Answer

As the planet moves from point A towards point B, it is moving away from the star and therefore experiences a decrease in the gravitational force acting upon it. Since the force of gravity is what is responsible for keeping the planet in orbit, the decrease in this force causes the planet's speed to decrease as well. Therefore, the correct choice is C.

The Figure Below Shows a Planet Traveling in a Clockwise