Planetary Motion
Physics ⇒ Earth and Space Physics
Planetary Motion starts at 8 and continues till grade 12.
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See sample questions for grade 12
A comet has a highly elliptical orbit. At which point in its orbit does it move slowest?
A planet is 4 times farther from the Sun than Earth. According to Kepler's Third Law, how many Earth years does it take to complete one orbit?
A planet orbits the Sun at a distance of 9 AU. What is its orbital period in Earth years?
A satellite orbits Earth at a height where the acceleration due to gravity is 4.9 m/s². If Earth's surface gravity is 9.8 m/s², what is the satellite's distance from Earth's center in terms of Earth's radius?
Describe how Newton's laws of motion and gravitation explain the elliptical orbits of planets.
Describe the difference between geocentric and heliocentric models of planetary motion.
Explain why the acceleration due to gravity decreases as you move farther from the center of a planet.
If a planet's orbital period is 27 years, what is the length of its semi-major axis in astronomical units (AU)? (Use Kepler's Third Law: T² = a³)
If the distance between two planets is tripled, the gravitational force between them becomes:
If the mass of a planet is doubled but its distance from the Sun remains the same, what happens to its orbital period?
If the mass of the Sun were doubled, what would happen to the gravitational force between the Sun and a planet at the same distance?
State Kepler's Third Law of Planetary Motion.
State Newton's Law of Universal Gravitation.
The orbital speed of a planet is greatest at which point in its orbit?
Which law states that the orbit of every planet is an ellipse with the Sun at one of the two foci?
Which scientist formulated the three laws of planetary motion?
A newly discovered exoplanet orbits its star at a distance where the gravitational acceleration is 2.5 m/s². If the star's mass is 2 × 1030 kg, calculate the orbital radius of the exoplanet. (G = 6.67 × 10-11 N·m²/kg²)
A planet has a mass of 6 × 1024 kg and orbits a star at a distance of 1.5 × 1011 m. If the gravitational force between the planet and the star is 3.5 × 1022 N, what is the mass of the star? (G = 6.67 × 10-11 N·m²/kg²)
A planet orbits a star of mass M at a distance r. Derive an expression for the orbital speed of the planet, assuming a circular orbit, using Newton's Law of Universal Gravitation and centripetal force.
Consider two planets, A and B, orbiting the same star. Planet A has an orbital period of 2 years and a semi-major axis of 1.6 AU. Calculate the semi-major axis of planet B if its orbital period is 8 years. (Use Kepler's Third Law: T² ∝ a³)
