Question

kepler’s first law established that: (1 point)
○ planet speed is constant throughout their orbits
○ planets move in elliptical orbits with the sun at one focus
○ gravitational force controls planetary motion
○ planets move in perfect circular orbits around earth

Explanation:

• Analyze each option:
• "Planet speed is constant throughout their orbits" is incorrect; Kepler's Second Law relates to speed variation.
• "Planets move in elliptical orbits with the sun at one focus" matches Kepler's First Law.
• "Gravitational force controls planetary motion" is related to Newton's work, not Kepler's First Law.
• "Planets move in perfect circular orbits around Earth" is the geocentric model, disproven, and not Kepler's First Law.

Answer:

B. Planets move in elliptical orbits with the sun at one focus