AY 101 002 CH 4 HW

Part complete As you watch the video, notice that the size of the tidal bulges varies with the Moon's phase, which depends on its orbital position relative to the Sun. Which of the following statement(s) accurately describe(s) this variation? Select all that apply. - High tides are highest at first- and third-quarter moon. - Low tides are highest at full moon and lowest at new moon. - High tides are highest at both full moon and new moon. - Low tides are highest at both full moon and new moon. - Low tides are lowest at both full moon and new moon. - High tides are highest at full moon and lowest at new moon.

- High tides are highest at both full moon and new moon. - Low tides are lowest at both full moon and new moon.

Which of the following are allowed orbital paths under gravity? Select all that apply. - square - getting sucked in by gravity - elliptical - hyperbolic - parabolic

- elliptical - hyperbolic - parabolic

The Moon's average density is about 3.34 grams per cubic centimeter. What is this density in units of pounds per cubic inch?

0.121 pounds per cubic inch

Consider again the experimental trials from Part A. This time, you wish to test how the size of an object affects the rate of its fall. Which pair of trials should you compare? Check exactly two of the following diagrams.

1 & 2

Part complete A planet with twice Earth's mass orbiting at a distance of 1 AU from a star with the same mass as the Sun.

1 year

1 megameter is ___________ times as large as 1 kilometer

10 ^3

1 centimeter is _________ times as large as 1 micrometer

10 ^4

1 hectometer is ________ times as large as 1 centimeter

10 ^4

1 gigameter is ___________ times as large as 1 kilometer

10 ^6

1 kilometer is ______ times as large as 1 millimeter

10 ^6

1 millimeter is __________ times as large as 1 nanometer

10 ^6

Each diagram shows a single experimental trial in which you will drop a ball from some height. In each case, the ball's size, mass, and height are labeled. Note that two diagrams show a basketball, one diagram shows a bowling ball of the same size but larger mass, and one diagram shows a much smaller marble with the same mass as the basketball. You have a timer that allows you to measure how long it takes the ball to fall to the ground. Which pair of trials will allow you to test the prediction that an object's mass does not affect its rate of fall?

2 & 4

The average distance from Earth to the Moon is 384,400 kilometers. What is this distance in miles, rounded to the nearest 100 miles?

238,900 miles

A common measure of health is the body mass index (BMI), defined as a person's weight in kilograms divided by the square of the person's height in meters. That is, BMI=mass (in kg)[height (in m)]2 Notice that the BMI is a number with no units, but you'll get the correct number only if you use the correct units in the calculation. Consider a man who is 6 feet tall and weighs 200 pounds. What is his body mass index?

27.13

A planet with the same mass as Earth orbiting at a distance of 1 AU from a star with four times the Sun's mass.

6 months

If the United States obtained all its energy from oil, how much oil would be needed each year? Express your answer using two significant figures.

8.3×10 ^12 liters

Which person is weightless?

A child in the air as she plays on a trampoline.

Which of the following represents a change from potential energy to kinetic energy?

A rock starting from rest on a high cliff, then moving faster and faster as it falls.

Suppose that the Sun were to collapse from its current radius of about 700,000 km to a radius of only about 6000 km (about the radius of Earth). What would you expect to happen as a result?

A tremendous amount of gravitational potential energy would be converted into other forms of energy, and the Sun would spin much more rapidly.

If you actually performed and compared the two trials chosen in Part C, you would find that, while the basketball and marble would hit the ground at almost the same time, it would not quite be exact: The basketball would take slightly longer to fall to the ground than the marble. Why?

Because air resistance has a greater effect on the larger ball.

Assume you have completed the two trials chosen in Part A. Which of the following possible outcomes from the trials would support Newton's theory of gravity? Neglect effects of air resistance.

Both balls fall to the ground in the same amount of time.

According to the law of universal gravitation, what would happen to Earth if the Sun were somehow replaced by a black hole of the same mass?

Earth's orbit would not change.

Compare the energy of a 1-megaton hydrogen bomb to the energy released by a major earthquake. Express your answer using one significant figure.

Eearthquake/Ebomb = 5

Compare the Sun's annual energy output to the energy released by a supernova.

Esupernova/ESun∼10 ^11

Suppose that two asteroids are orbiting the Sun on nearly identical orbits, and they happen to pass close enough to each other to have their orbits altered by this gravitational encounter. If one of the asteroids ends up moving to an orbit that is closer to the Sun, what happens to the other asteroid?

It will end up on an orbit that is farther from the Sun.

The table below shows the metric prefixes

Metric Prefixes Small Values Large Values Prefix Abbrev. Value Prefix Abbrev. Value Deci d 10−1 Deca da 101 Centi c 10−2 Hecto h 102 Milli m 10−3 Kilo k 103 Micro μ 10−6 Mega M 106 Nano n 10−9 Giga G 109 Pico p 10−12 Tera T 1012

As shown in the video, Earth has two tidal bulges at all times. Approximately where are these bulges located?

One faces the Moon and one faces opposite the Moon.

Einstein's theory, like Newton's, predicts that, in the absence of air resistance, all objects should fall at the same rate regardless of their masses. Consider the following hypothetical experimental results. Which one would indicate a failure of Einstein's theory?

Scientists dropping balls on the Moon find that balls of different mass fall at slightly different rates.

In Part A, you found that your weight will be greater than normal when the elevator is moving upward with increasing speed. For which of the following other motions would your weight also be greater than your normal weight?

The elevator moves downward while slowing in speed.

One tidal bulge faces toward the Moon because that is where the gravitational attraction between Earth and the Moon is strongest. Which of the following best explains why there is also a second tidal bulge?

The second tidal bulge arises because gravity weakens with distance, essentially stretching Earth along the Earth-Moon line.

Most people are familiar with the rise and fall of ocean tides. Do tides also affect land?

Yes, though land rises and falls by a much smaller amount than the oceans.

Suppose you are in an elevator car when the elevator cable breaks. Which of the following correctly describes what happens and why.

You float weightlessly within the elevator car because you and the elevator both begin to accelerate downward at the same rate.

If the Moon were closer to Earth, high tides would

be higher than they are now.

You have found that tides on Earth are determined primarily by the position of the Moon, with the Sun playing only a secondary role. Why does the Moon play a greater role in causing tides than the Sun?

because the gravitational attraction between Earth and the Moon varies more across Earth than does the gravitational attraction between Earth and the Sun

What tie is it at point 1?

cannot be determined from the information in the figure

Consider the statement "There's no gravity in space." This statement is:

completely false

Suppose two objects are attracting each other gravitationally. If you double the distance between them, the strength of their gravitational attraction __________.

decreases by a factor of 4

To make a rocket turn left, you need to:

fire an engine that shoots out gas to the right

A car is accelerating when it is

going around a circular track at a steady 100 miles per hour.

The video shows a collapsing cloud of interstellar gas, which is held together by the mutual gravitational attraction of all the atoms and molecules that make up the cloud. As the cloud collapses, the overall force of gravity that draws the cloud inward ________________ because ____________________________________.

gradually becomes stronger, the strength of gravity follows an inverse swaure law with distance

The gravitational potential energy of contracting interstellar cloud

gradually transforms into other forms of energy.

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

As a giant cloud of gas collapses due to gravity, you would expect its rate of rotation to

increase

As the cloud shrinks in size, its central temperature __________ as a result of its __________.

increases, gravitational potential energy being converted to thermal energy

Part complete 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 __________. (Be sure to note that the video does not show a situation in which the elevator is slowing while moving upward, so you will need to decide which portion of the video is relevant to this situation; Hint 1 may be helpful.)

less than your normal weight at rest

Compared to their values on Earth, on another planet your

mass would be the same but your weight would be different.

Find the appropriate labels to their respective targets. You may use the same label more than once, and not all labels will be used. - My friend is 2 _________ tall. - My water bottle has a volume of 1.5 ________. - My thumb is 2 _________ wide. - I bought 3 ___________ of apples at the store. - A penny weighs about 3 ___________. - I can run 60 ____________ in 10 seconds.

meters, liters, centimeters, kilograms, grams, meters

If Earth were twice as far from the Sun, the force of gravity attracting Earth to the Sun would be

one-quarter as strong

Where is it high tide?

points 1 and 3

Where is it low tide?

points 2 and 4

As the cloud shrinks in size, its rate of rotation _____________ because ________________________.

speeds up, its total angular momentum is conserved

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

What do the three black arrows represent?

the Moon's gravitational force at different points on Earth

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

the force you exert on the scale

Compared to its angular momentum when it is farthest from the Sun, Earth's angular momentum when it is nearest to the Sun is

the same

The light blue region represents tidal bulges. In what way are these bulges drawn inaccurately?

they should be much smaller compared to Earth

Any particular location on Earth experiences __________.

two high tides and two low tides each day