Test on Universal Gravitation

Two satellites of equal mass are in circular orbit around a planet. Satellite b is twice as far out. Which feels a stronger gravitational force?

• Satellite a

• Satellite b

• Both the same

Two satellites of equal mass are in circular orbit around a planet. Satellite b is twice as far out. How much stronger is the planet’s gravity on satellite a (compared to satellite b)?

• 2× as much

• 3× as much

• 4× as much

• 5× as much

What did Newton say about the gravitational force between distant objects?

• It is independent of distance

• It is inversely related to distance squared

• It is proportional to distance squared

• It is inversely related to mass squared

• It is zero, unless the objects are touching

Why do astronauts in this space shuttle feel weightless?

• They are in free fall, at the same rate as the shuttle

• There is an equal force pulling them away from Earth

• The gravity at that distance is too small to feel

• They pull on Earth as hard as it pulls on them

Which diagram best shows the gravitational interaction between Earth and a satellite?

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• 
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Earth pulls satellite, and satellite pulls Earth. Which of the forces is stronger?

• Earth pulling satellite

• Satellite pulling Earth

• Both the same

• Not enough information to determine

A student standing on Earth's surface weighs 100 pounds. How much would he weigh standing on a ladder as tall as Earth's radius?

• 400 pounds

• 200 pounds

• 100 pounds

• 50 pounds

• 25 pounds

You want to launch a satellite into Earth orbit. You already know Earth’s mass, and the satellite’s mass. What additional information do you need to calculate the gravitational force that will act on it?

• The height it will have

• The acceleration of gravity at the surface

• Earth's distance from the Sun

• The satellite's size

The value of eccentricity can range from ________ to ________.

• 0.1 to 0.9

• -1 to 0

• 0 to 100

• 0 to 1

The planets in our solar system all have ______________ orbits.

• spherical

• elliptical

• circular

• highly eccentric