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.
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)
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)
Which of the following best describes the relationship between a planet's orbital period (T) and its average distance from the Sun (a)?
(1) T² ∝ a³
(2) T ∝ a
(3) T³ ∝ a²
(4) T ∝ a²
Which of the following best describes the shape of planetary orbits according to Kepler?
(1) Circular
(2) Elliptical
(3) Parabolic
(4) Hyperbolic
Which of the following best explains why planets do not fall into the Sun?
(1) Their inertia balances gravitational attraction
(2) The Sun repels them
(3) They are moving too fast
(4) The Sun has no gravity
Which of the following is a direct consequence of Newton's Law of Universal Gravitation?
(1) Planets move in perfect circles
(2) All objects with mass attract each other
(3) The Sun is the heaviest object in the universe
(4) Gravity only acts on Earth
The eccentricity of a planet's orbit describes how much it deviates from being a ________.
The force that keeps planets in orbit around the Sun is called ________.
The gravitational force between two objects depends on their masses and the ________ between them.
The point in a planet's orbit closest to the Sun is called ________.
According to Kepler's Second Law, a planet moves fastest in its orbit when it is closest to the Sun. True or False?
The area swept out by a planet's radius vector in a given time is always the same, regardless of where the planet is in its orbit. True or False?
True or False: The total mechanical energy (kinetic plus potential) of a planet in a stable orbit around the Sun is always negative.
