Physics Ch 9
zero.
Half way to the center of a completely hollow planet with a thin uniform shell, your weight would be
strongest on the side of Earth closest to the Moon.
The Moon's gravitational pull is _________.
almost as much as the shuttle's weight on the Earth's surface.
The amount of gravitational force that acts on the space shuttle while in orbit is
simply the remains of a giant star that has undergone gravitational collapse.
A black hole is
Forget it; you can't travel far enough.
How far must one travel to get away from the Earth's gravitational field?
Yes, because the Sun's gravity still has an influence.
If there were no Moon, would there still be tides on Earth?
accelerate as you fall and cross the event horizon completely unhindered
If you were inside the rocket that falls toward the event horizon, from your own viewpoint you would __________.
at a constant, normal rate as you approach the event horizon
If you were inside the rocket that falls toward the event horizon, you would notice your own clock to be running __________.
Earth's orbit would not change.
Imagine that the Sun could be turned into a black hole without changing its mass. How would Earth's orbit change?
apparent weight for you.
Inside a freely falling elevator, there would be no
both inside and outside the Earth and throughout the entire universe.
The Earth's gravitational field extends
surface escape velocity.
The factor most directly responsible for making a black hole invisible is its
is greater on oceans closer to the moon and less on oceans farther from the moon.
The main reason ocean tides exist is that the pull of the moon
apparent weight is zero.
Inside a freely falling runaway elevator, your
yes
Is gravitational force acting on a person who falls off a cliff?
yes
Is gravitational force acting on an astronaut inside an orbiting space shuttle?
500 N.
What is the force of gravity on a 500-newton woman standing on the Earth's surface?
non-zero, directed towards the spaceship.
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, inhabitants find that the gravitational field inside the planet is
100 N.
A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above the Earth's surface. How much would she weigh there?
divides by 4 the gravitational force between them.
According to Newton, doubling the distance between two interacting objects
40 N.
An asteroid exerts a 360-N gravitational force on a nearby spacecraft. If the spacecraft moves to a position three times as far from the center of the asteroid, the force will be
toward the asteroid.
An asteroid exerts a 360-N gravitational force on a nearby spacecraft. This force is directed
Earth.
An object is placed exactly halfway between the Earth and moon. The object will fall toward the
6 hours.
Approximately how much time passes between low and high tide?
slows down as it approaches the event horizon, and never actually crosses the event horizon
As the falling rocket plunges toward the event horizon, an observer in the orbiting rocket would see that the falling rocket __________.
collapsed stars
Black holes are essentially _______.
none of these.
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is
there are two high tides and two low tides
Each day _______________.
that gravity is universal.
Newton discovered
always false.
No force due to Earth's gravity is acting on the astronauts inside the orbiting space shuttle. This statement is
increases.
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
practically the same weight.
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
The force decreases to one quarter.
What happens to the force of attraction between two planets when the distance between them is doubled?
remains the same.
When a star collapses to form a black hole, its mass
the moon.
Which is most responsible for the ocean tides?
when the Moon is high overheard.
A high tide can occur __________.
eliminates the role of force
Einstein's theory of gravitation, compared with Newton's, _______.
4
Find the change in the gravitational force between two planets if the masses of both planets are doubled but the distance between them stays the same.
Its light will become so redshifted that it will be undetectable.
From Part B, you know that from afar we'll never see the in-falling rocket cross the event horizon, yet it will still eventually disappear from view. Why?
Time runs increasingly slower as the rocket approaches the black hole.
From the viewpoint of an observer in the orbiting rocket, what happens to time on the other rocket as it falls toward the event horizon of the black hole?
The high tides during a full moon are roughly the same as the high tides during a new moon.
How do the high tides during a full moon compare to high tides during a new moon?
increase also.
If the mass of the Earth somehow increased with no change in radius, your weight would
(first quarter, third quarter), (new, full)
Which of the following lists correctly gives, in increasing order, the height of the high tides that occur during particular lunar phases? (Ties are denoted by parentheses.)
the sun.
Which pulls on the oceans of the Earth with the greater force?
