Astronomy Exam 2 Review

Which of the following is an example in which you are traveling at constant speed, but not at constant velocity?

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  Rolling freely down a hill in a cart, traveling in a straight line

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  Driving around in a circle at exactly 100 km/hr

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  Jumping up and down exactly 60 times per minute

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  Driving backward at exactly 50 km/hr

Momentum is defined as

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  mass times speed

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  mass times velocity

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  force times velocity

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  mass times acceleration

If your mass is 60 kilograms on Earth, what would your mass be on the Moon?

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  10 pounds

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  10 kilograms

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  60 kilograms

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  60 pounds

Astronauts are weightless inside the International Space Station because ________.

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  the station and the astronauts are constantly falling toward Earth at the same rate.

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  the station has rockets that fire to counteract Earth's gravity.

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  there is no gravity in space.

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  the station is too far from Earth for gravity to be noticeable.

If a net force is applied to an object, what is guaranteed to change?

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  The object's momentum

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  The object's speed

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  The object's mass

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  The object's weight

A comet has an elliptical orbit around the Sun. Its total orbital energy is ________.

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  greatest when it is farthest from the Sun

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  greatest when it is closest to the Sun

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  the same throughout its orbit

According to the universal law of gravitation, the force due to gravity is ________.

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  directly proportional to the square of the distance between objects

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  inversely proportional to the square of the distance between objects

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  directly proportional to the distance between objects

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  inversely proportional to the distance between objects

Which orbital shapes are possible under the force of gravity?

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  Ellipses only

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  Ellipses and spirals

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  Ellipses, parabolas, and hyperbolas

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  Ellipses, spirals, and parabolas

Which of the following describes a velocity (as opposed to a speed)?

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  20 kilometers per hour, headed north

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  300,000 kilometers per second

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  9.8 meters per second squared.

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  5 light-years

The energy attributed to an object by virtue of its motion is known as ________.

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  kinetic

• potential

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  radiative

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  mass-energy