What shape is the moon's orbit around Earth?
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2 points
an ellipse that is elongated
a spiral
a circle
an ellipse that is almost circular
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The shape of the moon's orbit around Earth is an ellipse that is almost circular.
Which did Kepler notice FIRST about planetary motion that caused him to propose Kepler’s first law of orbital motion?
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2 points
The planets have circular orbits.
The distance between Mars and the sun is constant.
The planets speed up and slow down but cover the same area.
Most planets have highly elliptical orbits.
The answer is "The planets speed up and slow down but cover the same area." This observation led Kepler to propose his first law of orbital motion.
For which project would knowledge of Kepler's laws prove most useful?
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2 points
calculating the mass of Earth
determining the structure of the solar system's planets
putting a communications satellite in Earth orbit
measuring the distance between Earth and the moon
Knowledge of Kepler's laws would prove most useful for determining the structure of the solar system's planets. Kepler's laws describe the motion of bodies in orbit around a central celestial object, such as planets around the sun. Therefore, understanding these laws would provide valuable insights into the arrangement and behavior of the planets in the solar system.
A line between a planet and the sun sweeps out two equal areas at different places as it moves along its orbit. Which factor remains constant as this happens?
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2 points
the time the planet takes to sweep out the areas
the distance from the sun to the planet while it sweeps out the areas
the planet’s speed as it sweeps out the areas
the energy required to sweep out the areas
The factor that remains constant as a line between a planet and the sun sweeps out two equal areas at different places is the planet's speed as it sweeps out the areas. According to Kepler's second law of planetary motion, the line connecting a planet to the sun sweeps out equal areas in equal time intervals. Since the areas are equal, the time taken to sweep them out must also be equal, meaning the planet's speed remains constant.
A highly eccentric orbit, such as a comet, will have an eccentricity of 0.
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1 point
True
False
False.
A highly eccentric orbit, such as a comet, will have an eccentricity greater than 0. The eccentricity of an orbit is a measure of how much it deviates from a perfect circle. A value of 0 represents a perfect circle, while values between 0 and 1 indicate an ellipse with varying degrees of elongation or eccentricity. Therefore, a highly eccentric orbit will have an eccentricity greater than 0.
Which was a belief of Copernicus's model of the solar system?
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2 points
The planets move in perfect circles.
All planets orbit the Sun at the same speed.
The outer planets move in epicycles.
Earth is fixed to a crystalline sphere.
A belief of Copernicus's model of the solar system was "The planets move in perfect circles." Copernicus proposed that the planets moved in circular orbits around the Sun, with the Sun at the center. This was in contrast to the prevailing geocentric model, which posited that Earth was at the center of the universe and that the planets moved in complex motions involving epicycles.
Which statement about the geocentric model is true?
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2 points
It shows the orbits of the planets as elliptical.
It shows Earth at the center of the solar system.
It shows the Sun at the center of the solar system.
The statement "It shows Earth at the center of the solar system" is true about the geocentric model. According to the geocentric model, Earth is considered to be at the center of the universe, with the other celestial objects, including the Sun and planets, orbiting around it. This belief was prominent in ancient times and was later challenged by the heliocentric model proposed by Copernicus.
Which of the following statements about Newton's theory of universal gravitation is true?
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2 points
Gravitational force increases as the distance between objects increases.
Gravitational force increases as mass of objects decreases.
Gravitational force increases as the mass of objects increases.
The theory applies only to objects on Earth.
The statement "Gravitational force increases as the mass of objects increases" is true about Newton's theory of universal gravitation. According to Newton's law of universal gravitation, the force of gravity between two objects is directly proportional to the product of their masses. Therefore, as the mass of objects increases, the gravitational force between them also increases.
An asteroid approaches Jupiter and is slung into a new trajectory around across the solar system. If it's eccentricity is greater than 1, which statement might be true?
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2 points
The asteroid slows down as it passes around Jupiter.
The asteroid continues out of the solar system, never to return.
The asteroid adopts an unusual orbit around the sun, such as an egg shape.
The asteroid falls into an regular orbit around Jupiter instead of the sun.
If an asteroid's eccentricity is greater than 1, the statement that might be true is "The asteroid continues out of the solar system, never to return." An eccentricity greater than 1 indicates a hyperbolic orbit, which means that the asteroid's trajectory would take it on a path that goes away from the sun and it will not return to orbit around the sun. Instead, it will continue on its new trajectory, possibly leaving the solar system entirely.
The mass of an object doubles. What happens to the gravitational force between it and another object, assuming they remain the same distance apart?
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2 points
The amount of the gravitational force decreases by one-half.
The amount of the gravitational force quadruples.
The amount of the gravitational force doubles.
The amount of the gravitational force remains the same.
If the mass of an object doubles while the distance between it and another object remains the same, the gravitational force between them will also double. This means the correct statement is "The amount of the gravitational force doubles." According to Newton's law of universal gravitation, the force of gravity is directly proportional to the product of the masses of the objects involved. Therefore, if one object's mass doubles, the gravitational force it exerts on another object will also double assuming the distance remains constant.
Based on Kepler's observations about planetary motion, what is the relationship between a planet's orbital velocity and its distance from the sun?
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2 points
The greater the distance, the slower the orbital velocity.
Distance has no effect on orbital velocity.
The greater the distance, the greater the orbital velocity.
As distance is cut in half, orbital velocity decreases.
Based on Kepler's observations about planetary motion, the correct relationship between a planet's orbital velocity and its distance from the sun is "The greater the distance, the slower the orbital velocity." Kepler's second law of planetary motion states that as a planet orbits the sun, it sweeps out equal areas in equal time intervals. This means that when a planet is closer to the sun, it covers a smaller distance in a given time, resulting in a higher orbital velocity. Conversely, when a planet is farther from the sun, it covers a larger distance in the same amount of time, leading to a slower orbital velocity.
Why was the geocentric model accepted for more than a thousand years?
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2 points
It correctly explained the motion of the planets.
It correctly described the solar system.
It was confirmed by astronomers using telescopes.
It correctly explained the distribution of the stars.
The geocentric model was accepted for more than a thousand years primarily because it correctly explained the motion of the planets as observed from Earth. Ancient astronomers observed that the planets appeared to move in complex patterns across the sky, including retrograde motion, where planets temporarily appear to move backward in the sky. The geocentric model, with Earth at the center, explained these observations by introducing concepts like epicycles and deferents, which allowed for the planets' irregular motion to be accounted for. Therefore, the acceptance of the geocentric model was primarily based on its ability to explain and predict the observed planetary motions.
Select the correct answer to complete the sentence. Gravitational force is said to be universal because:
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2 points
it operates in one direction.
it operates only within our solar system.
it applies mainly to planets and moons.
it applies to all objects.
The correct answer to complete the sentence is "it applies to all objects." Gravitational force is said to be universal because it applies to all objects with mass. It is a fundamental force that acts between any two objects, regardless of their size, distance apart, or location in the universe. Therefore, gravitational force is not limited to our solar system or specific types of celestial bodies but applies universally to all objects with mass.
Select the correct words to fill in the blanks to this sentence: As a planet draws away from the sun in its orbit, the gravity pull from the sun pulls _________on the planet and the planet's speed _________.
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2 points
forwards, decreases
backwards, decreases
backwards, increases
forwards, increases
The correct words to fill in the blanks to the sentence are "backwards, decreases."
As a planet draws away from the sun in its orbit, the gravity pull from the sun pulls backwards on the planet. This means that the gravitational force acts in the opposite direction of the planet's motion. Additionally, as the planet moves farther from the sun, the gravitational force weakens, causing the planet's speed to decrease.
Which factor is not needed when calculating the velocity of a satellite orbiting a planet?
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1 point
the mass of the satellite
the orbital radius of the satellite
the mass of the planet
the universal gravitational constant
The factor that is not needed when calculating the velocity of a satellite orbiting a planet is "the mass of the satellite."
When calculating the velocity of a satellite orbiting a planet, the necessary factors include the orbital radius of the satellite, the mass of the planet, and the universal gravitational constant. The mass of the satellite does not affect the velocity of its orbit around the planet. It only affects the gravitational force acting upon the satellite, which determines the necessary centripetal force to keep the satellite in orbit.