Kepler's Laws of Planetary Motion

What is Kepler's First Law?

• The planets orbit the sun in circular paths.

• The planets orbit the sun in spiral paths.

• The planets orbit the sun in elliptical paths.

• The planets orbit the moon in elliptical paths.

Who formulated Kepler's Laws of Planetary Motion?

• Johannes Kepler

• Albert Einstein

• Galileo Galilei

• Isaac Newton

What is the shape of the orbits described by Kepler's Laws?

• hyperbolic

• parabolic

• circular

• elliptical

What is Kepler's Second Law?

• The distance between a planet and the Sun is directly proportional to the time it takes to complete one orbit.

• The speed of a planet in its orbit is constant.

• A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

• The force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

What is the shape of the orbit if the eccentricity is 0?

• ellipse

• circle

• hyperbola

• parabola

Which is the correct definition of Kepler's 3rd Law of Planetary Motion?

• The planet's orbital radius-cubed is proportional to the planet's maximum orbital speed-cubed.

• The planet's orbital period-squared is proportional to the planet's orbital radius-squared.

• The planet's orbital period-cubed is proportional to the planet's maximum orbital speed-squared.

• The planet's orbital speed-squared is proportional to the planet's orbital radius-cubed.

At which position is the planet's orbital speed the fastest?

• Position #1

• Position #2

• Position #3

• Position #4

At which position is the planet's orbital speed getting faster?

• Position #1

• Position #2

• Position #3

• Position #4

At which position is the planet's orbital speed getting slower?

• Position #1

• Position #2

• Position #3

• Position #4

Which factor of a planet's motion best supports Kepler's 2nd law of motion?

• The gravitational attraction between the planet and the sun is constantly changing

• The planet moves at different orbital speeds at different places in its orbit.

• The planet's orbit is constantly changing size and shape because the sun is also moving relative to the planet.

• Over time, a planet's orbital radius is slightly decreasing, and all planets are gradually moving inward towards the sun.