ch9 physics hw

Consider Earth and the Moon. As you should now realize, the gravitational force that Earth exerts on the Moon is equal and opposite to that which the Moon exerts on Earth. Therefore, according to Newton's second law of motion __________.

the Moon has a larger acceleration than Earth, because it has a smaller mass

f you are standing on a scale in an elevator, what exactly does the scale measure?

the force you exert on the scale

Which two factors mainly affect ocean tides on Earth?

the moon and the sun

Why are occupants of the International Space Station weightless?

they are in free fall

What Newton discovered most about gravity is that it is _______.

universal

Which of the following quantities represent mass?

0.34 g and 120 kg

Which of the following quantities would be acceptable representations of weight?

12.0 lbs, 1600kN, and 899MN

Larry weighs 300 N at the surface of Earth. What is the weight of Earth in the gravitational field of Larry? Express your answer with the appropriate units.

300 N

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. Express your answer as an integer.

4

If the acceleration due to gravity on the earth is 9.8 m/s2m/s2, what is the acceleration due to gravity on Rams? Express your answer in meters per second squared and use two significant figures.

5.7 m/s^2

Earth's gravitational field is strongest at _______.

Earth's surface

When is your weight measured as mg?

For a non-accelerating mass near the surface of Earth

Which planet should Punch travel to if his goal is to weigh in at 118 lb? Refer to the table of planetary masses and radii given to determine your answer.

Pentune

The following diagrams are the same as those from Part A. Again considering only the two objects shown in each pair, this time rank the strength, from strongest to weakest, of the gravitational force acting on the object on the right.

Sun>Earth>Moon>Asteroid>Hydrogen Atom

The following diagrams are the same as those from Part A. This time, rank the pairs from left to right based on the size of the acceleration the asteroid on the left would have due to the gravitational force exerted on it by the object on the right, from largest to smallest.

Sun>Earth>Moon>Asteroid>Hydrogen Atom

The following five diagrams show pairs of astronomical objects that are all separated by the same distance ddd. Assume the asteroids are all identical and relatively small, just a few kilometers across. Considering only the two objects shown in each pair, rank the strength, from strongest to weakest, of the gravitational force acting on the asteroid on the left.

Sun>Earth>Moon>Asteroid>Hydrogen Atom

Why does the gravity in the Space Shuttle compare with the gravity on Earth the way it does?

The Space Shuttle and the surface of the Earth are about the same distance from the center of the Earth.

Why do the astronauts in the Space Shuttle float around?

The Space Shuttle is in free fall, so the shuttle and the astronauts inside it are continuously falling toward the Earth. They thus experience apparent weightlessness.

As you found in Part A, your weight will be greater than normal when the elevator is moving upward with increasing speed. For what other motion would your weight also be greater than your normal weight?

The elevator moves downward while slowing in speed.

How does the gravity in the Space Shuttle compare with the gravity on Earth's surface?

The gravity in the Space Shuttle is approximately equal to the gravity on the surface of the Earth

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is moving downward at a constant speed.

The upward force on the feet will be equal to the man's weight.

Predict how the upward force exerted on the feet by the scale will compare to the weight of the man if the elevator is moving upward at a constant speed.

The upward force on the feet will be equal to the man's weight.

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is accelerating downward.

The upward force on the feet will be less than the man's weight.

Predict how the upward force exerted on the feet by the scale will compare to the man's weight if the elevator is accelerating upward.

The upward force on the feet will exceed the man's weight.

Where do you weigh more: at the bottom of Death Valley or atop one of the peaks of the Sierra Nevada? Why?

You weigh more in Death Valley because you are closer to the center of Earth.

Give an example of when your weight is greater than mg. Give an example of when your weight is zero.

Your weight is greater than mg when you are accelerating upward. Your weight is zero when you are in free fall.

If acceleration due to gravity on the earth is ggg, which formula gives the acceleration due to gravity on Loput?

g=5.6/1.7^2

Suppose you are in an elevator. As the elevator starts upward, its speed will increase. During this time when the elevator is moving upward with increasing speed, your weight will be __________.

greater than your normal weight at rest

Suppose you are in an elevator that is moving upward. As the elevator nears the floor at which you will get off, its speed slows down. During this time when the elevator is moving upward with decreasing speed, your weight will be __________.

less than your normal weight at rest

The constant G in Newton's equation _______.

makes the units of measurement consistent

After Punch Taut travels to Pentune, what actually happens to his mass and his weight?

mass remains the same; weight decreases

An object is lifted from the surface of a spherical planet to an altitude equal to the radius of the planet. As a result, which of the following changes in the properties of the object take place?

mass remains the same; weight decreases

One's weightlessness in space has most to do with _______.

no support force

The gravitational field on the surface of the earth is stronger than that on the surface of the moon. If a rock is transported from the moon to the earth, which properties of the rock change?

weight only