Communications satellites are usually placed in circular orbits about 350,000 km above the surface of the Earth. Why don't we put them in lower orbits so that it would be easier to send and recieve radio and TV signals from them? Why don't we place them in elliptical orbits?
An object is placed exactly halfway between the Earth and the Moon. Which way will the object will fall? Why?
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. Where should he buy his metals and where should he sell them? Why would this scheme not work very well?
If there is an attractive force between all objects, why do we not feel ourselves gravitating toward massive buildings in our vacinity?
The Sun exerts almost 200 times more force on the oceans of the Earth than the Moon does. Why then, is the Moon more effective in raising tides?
Comment on whether or not this label on a consumer product would be cause for concern. CAUTION: The mass of this product pulls on every other mass in the universe, with an attractive force that is proportional to the product of the masses and inversely proportional to the square of the distance between them.
Which would have the greater effect on Earth's ocean tides--a Moon with a greater diameter, or the Earth with an increased diameter? Explain.
Issac Newton discovered
gravity.
that gravity is universal.
the telescope.
none of these.
According to Newton, the greater the masses of interacting objects, the
less the gravitational force between them.
greater the gravitational force between them.
According to Newton, the greater the distance between masses of interacting objects, the
more the gravitational force between them.
less the gravitational force between them.
If the mass of the Earth somehow increased with no change in radius, your weight would
decrease.
increase also.
stay the same.
Inside a freely falling elevator, there would be no
apparent weight for you.
gravitational force on you.
both of these.
none of these.
If the radius of the Earth somehow decreased with no change in mass, your weight would
not change.
increase.
decrease.
If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would
decrease to one-half your original weight.
stay the same.
decrease to one-quarter your original weight.
none of these.
The amount of gravitational force that acts on the space shuttle while in orbit is
almost as much as the shuttle's weight on the Earth's surface.
nearly zero.
the same as the shuttle's weight on the Earth's surface.
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
decreases.
remains constant.
increases.
Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each
decreases.
increases.
remains constant.
The force of gravity acts on all apples on an apple tree. Some apples are twice as far from the ground as others. These twice-as-high apples, for the same mass, have
practically the same weight.
1/4 the weight.
1/2 the weight.
When the distance between two stars decreases by half, the gravitaional force between them
decreases by one-half.
increases to four times as much.
decreases by one-quarter.
increases to twice as much.
The planet Jupiter is about 300 times as massive as the Earth, yet on its surface you would weigh only about 3 times as much. This is because
Jupiter is significantly farther from the Sun.
your mass is 100 times less on Jupiter.
Jupiter's radius is 10 times the Earth's radius.
you are 100 times more weightless there.
Inside a freely falling runaway elevator, your
apparent weight is zero.
acceleration is zero.
gravitational interaction with the Earth is zero.
all of these.
Each of us weighs a tiny bit less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper. The reason for this is the
gravitational field is shielded inside the building.
mass of the building attracts us upward slightly.
both of these.
none of these.
How far must one travel to get away from the Earth's gravitational field?
forget it; you can't travel far enough
to a region well beyond the Moon
to a region above the Earth's atmosphere
to a region beyond the solar system
Earth satellites are typically more than 100 km high so as to be above the Earth's
atmosphere.
gravitational field.
both of these.
What prevents satellites such as the space shuttle from falling?
centripetal force
gravity
the absence of air drag
Nothing, they continually fall all around the Earth.
An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is
farthest from the Earth.
nearest the Earth.
it travels at a constant speed everywhere in orbit.
The fastest moving planet in a solar system is
the planet nearest the Sun.
the planet farthest from the Sun.
the most massive planet.
the smallest planet.
A "weightless" astronaut in an orbiting shuttle is
like the shuttle, pulled by Earth's gravitation.
beyond the pull of gravity.
shielded from Earth's gravitational field.
pulled only by gravitation to the shuttle which cancels the Earth's gravitational pull.
The speeds of the planets about the Sun depend on
their distances from the Sun.
the masses of the planets.
both of these.
neither of these.
An object that moves around an external axis is said to be ____.
rotating
revolving
The distance around a circular object may correctly be called its ____.
diameter
radius
circumference
area
The force that exists between you and Earth is correctly identified as your ____.
mass
weight
inertia
aura
The oval-shaped orbit that satellites follow is called an ____.
apostrophe
ellipse
ecentric
eclipse
As comets approach the sun in their orbits, their speed ____.
increases
decreases
remains constant
Comets have no speed.
An example of rotation is ____.
Earth moving in its orbit around the sun
a basketball spinning on the end of a finger
a race car traveling at 200 miles per hour around a circular track
a student riding at the outside position on a merry-go-round
Three students are seated on a merry-go-round. Red is seated closest to the center, Blue is seated near the outer edge, and Yellow is seated between them. As the merry-go round turns ____.
Red has the greatest linear speed but the lowest angular speed
Blue has the highest linear speed and the same angular speed as the others
Yellow has the same linear speed as the others but the highest angular speed
All three students have the same linear and angular speed
Any force that causes an object to move in a circle is called ____ force.
gravitational
centripetal
linear
frictional
The source of the centripetal force that allows a race car to go around a corner is ____.
gravity
friction
inertia
momentum
The weight of an automobile depends upon all of the following factors EXCEPT the ____.
speed of the automobile on the road
mass of the earth
mass of the automobile
distance of the automobile from the Earth’s center
You cannot feel a gravitational force acting between you and a friend because ____.
gravity is a force applied only by Earth
living things do not exert any gravitational force
the mass of a person is not large enough to exert gravitational force strong enough to be felt
the distance between attracting objects must be very large for gravity to act
The path followed by one object as it revolves around another is called its ____.
trajectory
orbit
satellite
center of mass
Factors that affect the amount of centripetal force on an object moving in a circle include all of the following EXCEPT ____.
speed of the object
radius of revolution
mass of the object
direction of motion (clockwise or counterclockwise)
An airplane is circling an airport. The direction of the centripetal force on the airplane is directed ____.
away
toward the left
toward the right
toward the center
If you climb a hill, you are farther from the center of Earth. Due to your new location, your weight will ____.
decrease by a very tiny amount
increase by a very tiny amount
decrease by a large amount
increase by a large amount
The factor that will INCREASE your weight the MOST is ____.
doubling your mass
halving your mass
doubling your distance from the Earth’s center
halving your distance from the Earth’s center
If the radius of the curve around which a car is driven is increased, the following can be said about the centripetal force required to cause the car to go around the corner at constant speed:
The centripetal force increases.
The centripetal force decreases.
The centripetal force remains the same.
There is insufficient information to make a determination about the centripetal force.
A ball is being twirled clockwise on the end of a string. If the string is released when the ball reaches the point shown, the inertia of the ball will cause it to move ____.
along the curve
outward
left
center
The centripetal force on a 20-kilogram object revolving on the end of a 10-meter long cord is 20 newtons. If the linear speed of the object is doubled, the centripetal force required to keep it moving in a circle of the same radius is ____ newtons.
10
40
80
200
Examples of centripetal force include all of the following EXCEPT ____.
gravity of the sun acting to keep Earth in orbit
the door of a car pushing on a passenger as the car rounds a corner
the friction between a car and the track as the car accelerates straight down the drag strip
the force of the air pushing on the wings of a plane as it makes a turn
The gravitational force between two masses is 36 N. What is the gravitational force if the distance between them is tripled?
4.0 N
9.0 N
18 N
27 N
Two very large masses that are 10.0 cm apart gravitationally attract each other with a force of 10.0 N. When they are 5.0 cm apart, these masses will attract each other with what force?
