03.3-0.35 Orbits

An astronomy textbook, when printed out, weighs four pounds on the surface of the Earth. After finishing your course, you are so tired of the book, you arrange for NASA to shoot it into space. When it is twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book has been moving away from the Earth, not falling freely around it.)

• 4 lbs

• 8 lbs

• 2 lbs

• 1 lb

• 16 lbs

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NGSS.MS-PS2-4

NGSS.MS-PS2-5

Which of the following statements about the force of gravity is FALSE?

• it is a universal force, which acts everywhere in space

• its strength decreases as the square of the distance

• its strength is inversely proportional to the mass: the more mass, the less gravity

• the force never becomes zero

• it causes the paths of the planets to be ellipses and not straight lines

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NGSS.MS-ESS1-2

NGSS.MS-PS2-4

To come up with the precise mathematical form of his law of gravity, Newton first had to invent the mathematical techniques that we now call:

• algebra

• ratio and proportions

• angular momentum

• calculus

• scientific notation

In Newton's Law of Gravity, the force of gravity goes up as the:

• mass goes down

• distance goes up

• mass goes up

• distance goes down

• more than one of the above

Tags

NGSS.MS-PS2-4

Astronomers discover a new comet that orbits the Sun, but has its aphelion (the furthest point in its orbit) beyond Neptune. Astronomers studying this comet have the right to expect that it:

• will follow Newton’s laws of motion

• will move ahead in a straight line at a steady speed because of the law of inertia

• will not obey Newton’s universal law of gravitation

• will not have an equal and opposite force in empty space when the force of the Sun’s gravity pulls on it

• astronomer have no right to expect ANY of the above.

Tags

NGSS.HS-ESS1-4

NGSS.HS-PS2-1

NGSS.HS-PS2-4

Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling?

• the Shuttle is so far from the Earth, gravity is negligible

• the Shuttle's gravity balances the Earth's, so that the net gravity is zero

• the Shuttle is falling around the Earth (and everything aboard is in free fall)

• the Shuttle has an antigravity device on board, developed by NASA

• the rules Newton developed for gravity only hold on Earth, not once you get into space

Newton's reformulation of Kepler's third law allows us to measure the masses of bodies in orbit around each other, if we can measure:

• the rotation rate of each object

• the distances and periods of revolution

• the eccentricities and semi-major axes

• the force and the reaction force

• the sweetness of those fig-filled cookie bars

Tags

NGSS.HS-PS2-4

To figure out what you weigh on the surface of the Moon (how much gravity there pulls you downward), you need to know

• just the mass of the Moon

• just the distance from the Moon’s center to its surface

• just the size of the Moon’s orbit around the Earth (its semi-major axis, say)

• which part of its orbit the Moon is in

• two of the above factors

Tags

NGSS.MS-PS2-4

When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at:

• circular satellite velocity

• the minimum angular momentum point

• perihelion

• apogee

• the tail end of its journey

Tags

NGSS.MS-ESS1-2

NGSS.MS-PS2-4

The planet in our solar system whose orbit actually brings it inside the orbit of another planet is:

• Neptune

• Pluto

• Earth

• Mars

• Mercury