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Use the dictionary, the acronym finder, and the word origins dictionary (links above) as needed. A new quiz is available each Monday through Thursday. This is the quiz for December 3.

Kepler's laws of planetary motion are three mathematical laws that describe the motion of planets in the Solar System. German mathematician and astronomer Johannes Kepler (died 1630) discovered them.

His assertion that the Earth moves, his use of ellipses rather than epicycles, and his proof that the planets' speeds vary changed astronomy and physics. Almost a century later Isaac Newton was able to deduce Kepler's laws from Newton's own laws of motion and his law of universal gravitation.

In modern times, Kepler's laws apply where any relatively small body is orbiting a larger, relatively massive body, though the effects of atmospheric drag, relativity, and other nearby bodies can make the results insufficiently accurate for a specific purpose.

First law

"The orbit of every planet is an ellipse with the sun at a focus."

Second law

"A line joining a planet and the sun sweeps out equal areas during equal intervals of time."

Third law - planets distant from the sun have longer orbital periods than close planets.

1. An orbital period isA. a season of a planet.2. Kepler

B. the length of time it takes a body in space to go around once.

C. the path of a body in space.

D. how long it takes the earth to go around the sun once.A. was a contemporary of Newton.3. Whereas a circle has one focus (its center), an ellipse has

B. lived before Newton.

C. lived later than Newton.A. two focuses.4. An epicycle is

B. three focuses.

C. four focuses.

D. no focus at all.A. a circle.

B. an ellipse.

C. a circle that rolls around (inside or outside) another circle.

D. a polygon.

The information comes from Wikipedia.

Write down your answers and then see Answer Key below.

Answer Key: 1-B..........2-B..........3-A..........4-C

Corrections? Questions? Comments? E-mail Robert Jackson at robert15115@gmail.com.