Physics Test Review

Suppose the gravitational force between two massive spheres is 10 N. If the distance between the spheres is cut in half, what is the force between the two masses?

40 Newtons

Suppose the gravitational force between two masses is 10 newtons. If the magnitude of each mass doubles, what is the force between the masses?

40 newtons

Because Earth and the moon are gravitationally attracted towards each other, they will soon collide.

false

Because Earth is "falling" around the sun, it will eventually crash into it.

false

If Earth were its present size but twice as massive, we would weigh less.

false

If Earth were to disappear, the moon would still orbit the place where Earth was.

false

Each of us weighs a tiny bit less on the ground floor of a skyscraper than we do on the top floor. One reason for this is that -

the mass of the building attracts you upward slightly

The reason the moon does not fall into Earth is that -

the moon has a sufficiently large orbital speed

The force on a ball decreases as the ball moves farther from Earth.

true

There is a force on Earth that is directed toward the sun.

true

Newton hypothesized that the moon -

Is a projectile Is falling around Earth Has tangential velocity that prevents it from falling into Earth Is actually attracted to Earth

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

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

The force of attraction between two masses depends inversely on the square of the distance between the masses. Any law that has this kind of dependence on distance is called an inverse distance law.

false

Newton had the insight to see that the -

force on the moon has the same nature as the force on an apple

Suppose the gravitational force between two masses is 10 newtons. If the volume of each mass doubles, while everything else stays the same, what is the force between the masses?

10 Newtons

A 400 Newton woman stands on top of a very tall ladder so she is one Earth radius above Earth's surface. How much does she weigh?

100 Newton

Suppose the gravitational force between two massive spheres is 10 newtons. If the distance between the spheres is doubled, what is the force between the masses?

2.5 Newtons

Since Earth is attracted to the sun, why doesn't it fall into the sun?

Because it has sufficient tangential velocity

Why did Newton think there was a force acting on the moon?

Because the moon moves in a curved path

A very massive object A and a less massive object B move toward each other under the influence of mutual gravitation. Which force, if either, is greater?

Both forces are the same

Which is more, the gravitational force between Earth and the moon, or between Earth and the sun?

Earth-sun

Consider the gravitational force between the 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 -

Quadruple

Compare the gravitational force between Earth and Mars, and the gravitational force between a newborn baby and the doctor who holds it. The greater force is between -

The baby and doctor

By noticing that Uranus's orbit is perturbed and by using the law of gravitation, two astronomers independently discovered -

Uranus has several moons

Gravitational forces are the weakest forces found in nature. Because of this -

gravitational forces that are easily observed involve one or more large masses

If the mass of Earth increased, with no change in radius, your weight would -

increase

If the radius of Earth decreased, with no change in mass, your weight would

increase

Two objects move toward each other because of gravitational attraction. As the object gets closer and closer, the force between them -

increases

The force of gravity on you is greatest when you are standing -

just below Earth's surface

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

A lunar month is about 28 days. If the moon were closer to Earth than it is now, the lunar month would be -

less than 28 days

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, directed toward the spaceship

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 atop the ladder would be -

one-quarter its normal value

Newton reasoned that the gravitational attraction between Earth and the moon must be -

reduced by distance

The force of gravity acting on you will increase if you -

stand on a planet that is shrinking

According to Newtons's laws, a rock and a pebble will fall at the same acceleration in a gravitational field because -

the ration of force / mass is the same for both

Some scientist think think that the universe we live in is oscillating.

true

The component of an orbiting satellite's velocity that is parallel to Earth's surface is its tangential velocity.

true