Kepler's First Law of Planetary Motion

Kepler's First Law of Planetary Motion states that the orbits of planets are:

• circular

• elliptical

• hyperbolic

Kepler's First Law is also known as the Law of ________.

• Ellipses

• Orbits

• Motion

According to Kepler's First Law, planets move in perfect circles around the Sun.

• True

• False

In Kepler's First Law, what is located at one of the foci of a planet's elliptical orbit?

• The Sun

• A black hole

• A planet

What is an ellipse?

• a perfect circle

• a straight line

• a closed curve on a plane with two foci

The shape of an ellipse is determined by its ____, a measure of how much the ellipse deviates from being a circle.

• eccentricity

• radius

• circumference

The shape of an ellipse is determined by:

• its major and minor axes

• its radius

• its circumference

What was the prevailing belief about planetary orbits before Kepler's discovery?

• Planets moved in ellipses.

• Planets moved in perfect circles.

• Planets moved in parabolas.