4.5 Kepler's Laws of Planetary Motion Review

What shape do planets follow in their orbits around the Sun?

• Circle

• Ellipse

• Square

• Parabola

According to Kepler’s First Law, where is the Sun located in a planet’s orbit?

• At the exact center

• At one focus of the ellipse

• Outside the orbit

• Equidistant from all points

Which of the following best describes an ellipse?

• A perfect circle

• A shape with two foci where the sum of distances remains constant

• A triangle with equal sides

• A straight line

What does Kepler’s Second Law state?

• Planets move at a constant speed in their orbits

• Planets travel in circular paths

• A planet sweeps out equal areas in equal times

• A planet’s orbit is affected by its rotation

When is a planet moving the fastest in its orbit?

• At perihelion (closest to the Sun)

• At aphelion (farthest from the Sun)

• When it is halfway through its orbit

• It moves at the same speed throughout

What happens to a planet’s speed as it moves away from the Sun?

• It increases

• It decreases

• It stays the same

• It moves in reverse

Kepler’s Third Law establishes a relationship between:

• A planet’s mass and temperature

• A planet’s orbital period and its distance from the Sun

• The gravitational pull of the Moon and Earth

• The rotation speed of planets

What does a higher eccentricity value mean for a planet’s orbit?

• The orbit is more circular

• The orbit is more elongated

• The orbit is stationary

• The planet moves in a straight line

What is the eccentricity of a perfect circle?

• 1

• 0

• 0.5

• -1

What force is responsible for keeping planets in orbit?

• Friction

• Gravity

• Magnetism

• Inertia