Gravity Practice Test
An object is placed exactly halfway between Earth and the moon. The object will fall toward
A. Earth
Since Earth is attracted to the sun, why doesn't it fall into the sun
A. because it has sufficient tangential velocity
The speed of a satellite in a circular orbit is
A. constant
Two objects move toward each other because of gravitational attraction. As the objects get closer and closer, the force between them
A. increases
if the sun were to collapse to form a black hole (quite unlikely), Earth would
D. orbit the black hole just as it orbits the sun now
Because Earth is falling around the sun, it will eventually crash into it
False
The gravitational force of Earth on an object does not depend upon the object's mass
False
An Earth satellite is a projectile that falls around Earth instead of falling into it
True
For some massive stars, gravitational collapse doesn't stop until the density of the star becomes so enormous that even light cannot escape. Such a star becomes a black hole
True
The force on a ball decreases as the ball moves farther from Earth
True
The place in a satellite's orbit where the satellite is closest to Earth is the perigee
True
The place in a satellite's orbit where the satellite is farthest from Earth is the apogee
True
The curvature of Earth is such that for every 8000 m tangent to the surface, the surface drops about
a. 5m
When a star collapses to form a black hole, its mass
a. remains the same
If you were to weigh yourself in an elevator that is in free fall, compared to your ordinary weight, you would weigh
a. zero
An object dropped from rest almost infinitely far from Earth falls to Earth because of Earth's gravitational field, and strikes the surface with a speed of about
b. 11 km/s
What remains constant for a satellite in elliptical orbit
b. its total energy
Minimal orbital speed about Earth is approximately 8 km/s. Minimal orbital speed about the moon would be
b. less than 8 km/s
the reason the moon does not fall into earth is that
b. the moon has a sufficiently large orbital speed
The fastest moving planet in a solar system is
b. the planet nearest the sun
Escape speed from the surface of Earth is about
c. 11.2 km/s
Where does a satellite in an elliptical orbit have the greatest kinetic energy
c. 8 km/s
The reason satellites orbit Earth at least 150 km above the surface is to
c. be above Earth's atmosphere
If you could throw a baseball horizontally at a speed of 8 km/s and if there were no air drag and nothing to stop it
c. it would orbit Earth
If you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weigh
c. more
The speed of a satellite in an elliptical orbit is
c. not constant
There are two main processes going on in the sun that keep the sun in existence. These processes are gravitation and
c. nuclear fusion
Consider the gravitational force between Earth and a meteor in outer space. If the meteor moves so its distance from the Earth's center doubles, the gravitational force on the meteor will be
c. one quarter
A projectile is fired vertically from the surface of Earth at 10 km/s. The projectile will
c. rise and then fall back to Earth's surface
The gravitational field strength at the center of Earth is
c. zero
The orbital speed for a satellite orbiting very close to Earth's surface is
d. 8000 m/s
the gravitational force between two massive spheres
d. all of the above
A period of a satellite is defined as
d. the time for a satellite to make one complete revolution around Earth
Newton hypothesized that the moon
e. all of the above
Gravitational forces are the weakest forces found in nature. Because of this
e. gravitational forces that are easily observed involve one or more large masses
