Chapter 3: Gravitation Flashcards
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What is Newton’s Universal Law of Gravitation?
Newton’s Universal Law of Gravitation states that every particle in the Universe attracts every other particle with a force that is:
Directly proportional to the product of their masses.
Inversely proportional to the square of the distance between their centers.
What is the formula for Newton’s Universal Law of Gravitation?
F = (G * m₁ * m₂) / r²
Where:
F = Force of gravity
G = Gravitational constant (6.67 × 10⁻¹¹ N m² kg⁻²)
m₁ = Mass of the first object
m₂ = Mass of the second object
r = Distance between the centers of the two objects
What is gravitational acceleration (g)?
Gravitational acceleration (g) is the acceleration experienced by an object due to the gravitational force of a larger object, like a planet. On Earth, g is approximately 9.81 m/s².
How is gravitational acceleration (g) related to the Universal Gravitational Constant (G)?
The formula for gravitational acceleration (g) is derived from Newton’s Law of Gravitation:
g = (G * M) / r²
Where:
M = Mass of the larger object (e.g., Earth)
r = Distance from the center of the larger object
What are Kepler’s Laws of Planetary Motion?
Kepler’s Laws describe the motion of planets around the Sun:
Law of Orbits: Planets move in elliptical orbits with the Sun at one focus.
Law of Areas: A line connecting a planet to the Sun sweeps out equal areas in equal times. (This means planets move faster when closer to the Sun).
Law of Periods: The square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit.
What is a geostationary satellite?
A geostationary satellite orbits the Earth at a specific height (about 35,786 km) and with a period of 24 hours. This means it appears to stay in the same position relative to the Earth, making it useful for communications.
What is a non-geostationary satellite?
A non-geostationary satellite orbits the Earth at a different height or with a different period than a geostationary satellite. It appears to move across the sky relative to the Earth.
What is escape velocity?
Escape velocity is the minimum speed an object needs to escape the gravitational pull of a planet or other celestial body. It depends on the mass of the planet and the distance from its center.
What is centripetal force?
Centripetal force is the force that keeps an object moving in a circular path. It always points towards the center of the circle. For satellites orbiting Earth, gravity provides the centripetal force.
How do man-made satellites benefit human life?
Man-made satellites have many applications:
Communication: They relay signals for TV, phones, and internet.
Navigation: They provide data for GPS systems.
Earth Observation: They monitor weather, track natural disasters, and map the Earth’s surface.
Scientific Research: They study the Earth, the Sun, and other planets.
