4-4 Kepler's Laws of Motion

Front

What are Kepler's Laws of Motion?

Back

Kepler's Laws of Motion describe the motion of planets around the sun, consisting of three laws: 1) The Law of Orbits: planets move in elliptical orbits with the sun at one focus. 2) The Law of Areas: a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time. 3) The Law of Periods: the square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

Front

What shape do the orbits of planets take according to Kepler's First Law?

Back

Ellipses.

Front

What is perihelion?

Back

The point in the orbit of a planet where it is closest to the Sun.

Front

What is aphelion?

Back

The point in the orbit of a planet where it is farthest from the Sun.

Front

During which month does the Earth move the slowest in its orbit?

Back

July.

Front

During which month does the Earth move the fastest in its orbit?

Back

January.

Front

What does Kepler's Second Law state?

Back

A line segment joining a planet and the sun sweeps out equal areas during equal intervals of time, meaning a planet moves faster when it is closer to the sun.

Front

What is the significance of Kepler's Third Law?

Back

It relates the orbital period of a planet to its distance from the sun, stating that the square of the orbital period is proportional to the cube of the semi-major axis of its orbit.

Front

How does the distance from the sun affect a planet's speed?

Back

A planet moves slower when it is farthest from the sun (aphelion) and faster when it is closest to the sun (perihelion).

Front

What is the semi-major axis in an elliptical orbit?

Back

The longest radius of an ellipse, which is half the longest diameter.