Question

which statement summarizes keplers first law of planetary motion? (1 point)
○ planets in the solar system revolve around the sun.
○ planets move fastest while earth is at perihelion.
○ planets revolve around the sun in elliptical orbits.
○ planets closest to the sun move faster in their orbits than those farther away.

Explanation:

Kepler's First Law of Planetary Motion states that the orbit of a planet around the Sun (or a satellite around a planet) is an ellipse with the Sun (or the planet) at one of the two foci. Let's analyze each option:

• The first option ("Planets in the solar system revolve around the sun") is a general statement about planetary motion but not specific to Kepler's First Law.
• The second option ("Planets move fastest while Earth is at perihelion") is incorrect as it mixes concepts and doesn't relate to the shape of orbits.
• The third option ("Planets revolve around the sun in elliptical orbits") matches the definition of Kepler's First Law.
• The fourth option ("Planets closest to the sun move faster in their orbits than those farther away") is related to Kepler's Second Law (law of equal areas in equal times, which also implies orbital speed variation with distance), not the first law.

Answer:

C. Planets revolve around the sun in elliptical orbits. (Note: Assuming the options are labeled A, B, C, D with the third option being C. If the original labeling is different, adjust the identifier accordingly, but the text "Planets revolve around the sun in elliptical orbits" is the correct summary of Kepler's First Law.)