Section 1
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Escape speed from the earth's surface is
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Last updated
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Date created
Mar 1, 2020
Cards (64)
Section 1
(50 cards)
Escape speed from the earth's surface is
11.2 km/s
The force of gravity acting on you will increase if you
Stand on a planet with a radius that is shrinking
An object is placed exactly halfway between earth and the moon. The object will fall toward
The earth
Two objects move toward eachother because of gravitational attraction. As the objects get closer and closer, the force between them
Increases
Since the earth is attracted to the sun, why doesn't it fall into the sun?
Because it has sufficient tangential velocity
Where does a satellite in an elliptical orbit have the greatest KE?
At the point closest to the planet
The speed of a satellite in a circular orbit is
Constant
The gravitational force between two massive spheres
Is always an attraction, depends on how massive they are, and depends inversely on the square of the distances between them
The gravitational field strength at the center of the earth is
Zero
The reason that satellites orbit the earth at least 150 km above the surface is to
Be above earth's atmosphere
If you were to weigh yourself in an elevator that is in free fall, compared to your ordinary weight, you would weigh
Zero
The force of gravity on you is the greatest when you are standing
Just below earth's surface
The curvature of earth is such that for every 8000vm tangent to the surface, the surface drops about
5 m
If earth's mass decreased to one half its original mass, with no change in radius, then your weight would
Decrease to one half of your original weight
Each of us weighs a tiny bit less on the ground floor of a skyscraper than we do on the top floor. One reason is that
The mass of the building attracts you upward slightly
If you stood atop a ladder on earth that was as tall as earth's radius (so you were twice as far from earth's center) your weight stop the ladder would be
One quarter it's normal value
Newton hypothesized that the moon
The moon is a projectile which is falling around earth and has a tangental velocity that prevents it from falling into earth. It is also attracted to earth
If the mass of the earth increased, with no change in radius, your weight woukd
Increase also
If you drop a stone into a hole drilled all the way to the other side of the earth, the stone will
Speed up until it gets to the center of the earth
A projectile is fired vertically from the surface of earth at 10 km/s. The projectile will
Rise and then fall back to the earth's surface
Which is greater, the gravitational force between earth and the moon, or the force between earth and the sun?
Earth and the sun
Why did Newton think there was a force acting on the moon?
Because the moon moves in a curved path
Jupiter has more than 300 times the mass of earth. Yet on Jupiter's surface an object weighs only about 3 times as much as it would on earth. The explanation to this involves Jupiter's
Large radius
Minimal orbital speed about earth is approximately 8 km/s. Minimal orbital speed about the moon would be
Less than 8 km/s
A planet has half the mass of the earth and half the radius. Compared to its weight on earth, an apple on this planet would weigh
Twice as much
Gravitational forces are the weakest fources found in nature. Because of this
Gravitational forces that are easily observed involve one or more large masses
Compared to the period of a satellite in orbit close to earth, the period of a satellite in orbit far from earth is
Longer
A supplier wants to make a profit by buying metal by weight at one altitude and selling it at the same price per pound at another altitude. The supplier should
Disregard altitude because it has a negligible effect
A lunar month is about 28 days. If the moon were closer to the earth than it is now, the lunar month would be
Less than 28 days
The fastest moving planet in the solar system is
The planet nearest the sun
If you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weigh
More
A very massive object A and a less massive object B move toward eachother under the influence of mutual gravitation. Which force, if either, is greater?
Both forces are the same
If the radius of the Earth decreased with no change in mass, your weight would
Increase
If you stand on a weight scale in an elevator that is accelerating upwards, why do you observe an increase in your weight?
Because you are accelerating upwards, there is more compression of the springs of the scale. The weight reading on the scale reflects the amount of compression of the springs
The circular orbit of a satellite orbiting earth is characterized by a constant
Speed, radius, and magnitude of acceleration
Where does a satellite in a circular orbit have the greatest KE?
Anywhere- the KE is constant
Newton had the insight to see that the
Force on the moon has the same nature as the force on an apple
The force of gravity on you is greatest when you are standing
On earth's surface
As a satellite is moving in orbit around the earth, the sum of the KE and PE everywhere is
Constant
If a weight scale shows that you weigh 200 kg on the surface of the earth, and then you sky dive with both of your feet attached to the scale, you will read a weight of
0 kg
A vertically oriented rocket that maintains a continuous upward velocity of 8 km/s will
Escape earth
The reason the moon does not fall into the earth is that
The moon has a sufficiently large orbital speed
Compared to the gravitational field on the surface of the earth, the gravitational field well below earth's surface is
Smaller
A hollow spherical planet is inhabited by people who live inside it, where the gravitational field is zero. When a very massive space ship lands on the planet's surface, the gravitational field inside the planet is
Nonzero and directed toward the space ship
The higher a satellite
Less it's speed is and the longer it's period is
Which of the following describes how circular and elliptical satellite orbits vary?
In a circular orbit, neither the distance to earth nor the speed of the satellite vary. In an elliptical orbit, both the distance to earth and the speed of the satellite vary
Newton reasoned that the gravitational attraction between earth and the moon must be
Reduced by distance
Consider the gravitational force between earth and a meteor in outer space. If the meteor moves so it's distance from the earth's center doubles, the gravitational force on the meteor will be
One quarter
A period of a satellite is defined as
The time for a satellite to make one complete revolution around earth
What remains constant for a satellite in elliptical orbit
It's total energy
Section 2
(14 cards)