These are the answers to the Orbital Motion Unit Test 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?
--> the time required to sweep out the areas

An asteroid approaches Jupiter and is slung around into a new trajectory across the solar system. Which of the following are possible? Select the three correct answers.
--> The asteroid spirals into the sun.
--> The asteroid enters a stable elliptical orbit around the sun.
--> The asteroid continues out of the solar system.

Which did Kepler notice about planetary motion that caused him to propose Kepler’s first law of orbital motion?
--> The distance to the sun varies.

Which statements about the geocentric model are false? Select the two correct 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.

The gravitational force between two objects is 360 Newtons. The objects move such that their distance is now three times their original distance. What is the new gravitational force between the objects?
--> 40 Newtons

For which project would knowledge of Kepler's laws prove most useful?
--> putting a communications satellite in Earth orbit

Which of the following statements about Newton's theory of universal gravitation are true? Select the three correct 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.

A satellite is orbiting Earth at an orbital radius of 7.3 x 10^m. What is its velocity in terms of G and the mass of Earth, mp? (Ignore units in the answer.)
--> (3.7×10^−3) square root of Gmp

For a moon orbiting its planet, rp is the shortest distance between the moon and its planet and ra is the longest distance between the moon and its planet. What is a moon's orbital eccentricity if rp is equal to 0.27ra
--> 0.57

Which form of Kepler’s third law can you use to relate the period T and radius r 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?
--> T^2 = r^3

Which are features of Copernicus's model of the solar system? Select the three correct answers.
--> The planets move in perfect circles.
--> The Sun is at the center.
--> The stars are fixed to an outer sphere.

What shape is the moon's orbit around Earth?
--> an ellipse that is almost circular

A satellite orbiting Earth at an orbital radius r has a velocity v. Which represents the velocity if the satellite is moved to an orbital radius of 3r?
--> 1/square root of 3 v