Answer: Orbital Motion Unit Test
1. 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?
Answer: The time required to sweep out the areas.
2. Which are features of Copernicus's model of the solar system? Select three correct answers.
Answers: The sun is at the center.
The planets move in perfect circles.
The stars are fixed to an outer sphere.
3. An asteroid approaches Jupiter and is slung around around into a new trajectory across the solar system. Which of the following are possible? Select three correct answers.
Answers: The asteroid spirals into the sun.
The asteroid continues out of the solar system.
The asteroid enters a stable elliptical orbit around the Sun.
4. A satellite orbiting the Earth at an orbital radius <em>r</em> has a velocity <em>v</em>. Which represents the velocity if the satellite is moved to an orbital radius of <em>5r</em>?
Answer: 1/√5 v
5. Which did Kepler notice about planetary motion that caused him to propose Kepler's first law of orbital motion?
Answer: The distance to the Sun varies.
6. Which statements about the geocentric model are false? Select two correct answers?
Answers: It explains why Mars appears to move backward for a few months approximately every two years.
It shows the Sun at the center of the solar system.
7. The mass of an object doubles. What happens to the gravitational force between it and another object whose mass stays the same, assuming they remain the same distance apart?
Answer: The amount of the gravitational force doubles.
8. What shape is the moon's orbit around Earth?
Answer: An ellipse that is almost circular.
9. Which of the following statements about Newton's theory of universal gravitation are true? Select the three correct answers?
Answers: The theory applies to all objects in the universe.
Gravitational force increases as the distance between objects decreases.
Gravitational force increases as the mass of objects increases.
10. Which form of Kepler's third law can you use to relate the period <em>T</em> and radius <em>r</em> of a planet in our solar system as long as the unit year is used for the period and astronomical unit is used for the radius?
Answer: <em>T²= r³</em>
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11. Based on Kepler's observations about planetary motion, what is the relationship between a planet's orbital velocity and its distance from the Sun?
Answer: The greater the distance, the slower the orbital velocity
12: For a moon orbiting its planet, <em>rp</em> is the shortest distance between the moon and its planet and <em>ra</em> is the longest distance between the moon and its planet. What is a moon's orbital eccentricity if <em>rp</em> is equal to <em>0.27ra</em>?
Answer: 0.57
Explanation:
Sorry I didn't do the short answer questions but these are all the correct answers to the science unit test.
