Phys 1404 2

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.

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.

Under what circumstances can energy level transitions occur?

Electrons can make a transition from one level to another by taking in or emitting a specific amount of energy. If too much or too little energy is offered, the electron cannot make the transition.

Comte was proven wrong in his claim that we could never learn the composition of stars. What do we know today that Comte did not know when making his claim, and that makes it possible for us to learn the chemical compositions of stars?

Every chemical element produces a unique spectral fingerprint.

Suppose you are aboard a rocket that is orbiting Earth in the low, circular orbit shown. If you want to escape from Earth and head to the Moon or Mars along the "escape" path shown, what do you need to do?

Fire the rocket engine in your direction of travel, so that you gain speed.

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?

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

If an astronaut goes on a space walk outside the Space Station, she will quickly float away from the station unless she has a tether holding her to the station. Choose the correct explanation why does the statement make sense (or is clearly true) or does not make sense (or is clearly false).

This statement is false. She and the Space Station share the same orbit and will stay together unless they are pushed apart.

If a distant galaxy has a substantial redshift (as viewed from our galaxy), then anyone living in that galaxy would see a substantial redshift in a spectrum of the Milky Way Galaxy. Choose the correct explanation why the statement makes sense (or is clearly true) or does not make sense (or is clearly false).

This statement makes sense. The redshift means that we see the galaxy moving away from us, so observers in that galaxy must also see us moving away from them—which means they see us redshifted as well.

What type of visible light spectrum does the Sun produce?

an absorption line spectrum

Interferometry uses two or more telescopes to achieve:

an angular resolution equivalent to that of a much larger telescope.

Click "show" for the emission line spectrum, then click "choose gases" and study the emission line spectrum for neon. The neon "OPEN" sign appears reddish-orange because __________

neon atoms emit many more yellow and red photons than blue and violet photons

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 absorption line spectrum shows what we see when we look at a hot light source (such as a star or light bulb) directly behind a cooler cloud of gas. Suppose instead that we are looking at the gas cloud but the light source is off to the side instead of directly behind it. In that case, the spectrum would __________.

be an emission line spectrum

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

The set of spectral lines that we see in a star's spectrum depends on the star's:

chemical composition.

Ionization is the process by which

electrons escape from atoms.

We could probably learn more about Mars by sending a new spacecraft on a flyby than by any other method of studying the planet.

false

How much greater is the light-collecting area of a 6-meter telescope than a 3-meter telescope?

four times

As an interstellar gas cloud shrinks in size, its gravitational potential energy:

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

Which of the following statements correctly state general principles of motion? (Assume that the moving object's mass is not changing.)

-Accelerated motion includes any motion involving a change in speed, change in direction, or both. -An object that is accelerating is also being acted upon by a (nonzero) net force. -An object that is accelerating is also undergoing a change in momentum.

Large telescopes often have small fields of view. For example, the Hubble Space Telescope's (HST's) advanced camera has a field of view that is roughly square and about 0.06 degree on a side. Calculate the angular area of the HST's field of view in square degrees.

0.0036 square degrees

Which person is weightless?

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

Choose the correct definition of a molecule.

A molecule is a group of two or more atoms bound together.

Why does a geostationary satellite must orbit around Earth's equator, rather than in some other orbit (such as around the poles)?

A satellite on non-equatorial orbit would show daily motion even if its period is exactly 1 sidereal day.

The diffraction limit is a limit on:

A telescope's angular resolution.

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.

Why does a geostationary satellite must orbit Earth in 1 sidereal day, rather than 1 solar day?

Actual period of the Earth's rotation is sidereal day. Solar day is a bit longer because of the Earth's orbital motion.

Which type is the Sun's visible-light spectrum, and why?

An absorption line spectrum. Relatively thin photosphere of the Sun absorbs the specific wavelength from the light emitted from the hot and dense interior of the Sun.

Choose the correct definition of an atom's atomic mass number.

An atom's atomic mass number is the number of protons plus the number of neutrons.

Choose the correct definition of an atom's atomic number.

An atom's atomic number is the number of protons it has in its nucleus.

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.

How do the angular resolutions you found in parts A and B compare to the angular resolution of the Hubble Space Telescope? Comment on the challenge of making images of planets around other stars.

Both planets could be distinguished from the Sun in means of angular resolution. However, the light from planets could be lost in the glare of the Sun.

Suppose we want to know what the Sun is made of. What should we do?

Compare the wavelengths of lines in the Sun's spectrum to the wavelengths of lines produced by chemical elements in the laboratory.

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

Completely false.

Why do dishes that aren't themselves heated by the microwave oven sometimes still get hot when you heat food on them? (Note: It's not a good idea to put empty dishes in a microwave.)

Conduction from heated food heats the dish.

How do the spectra of the different types of light bulbs compare?

Incandescent light bulbs emit generally continuous thermal spectra. CFLs and LEDs emit the light in the broad bands near specific wavelengths.

Why CFLs and LEDs can be much more energy efficient than incandescent bulbs?

Incandescent light bulbs emit most of consumed energy in infrared wavelengths. CFLs and LEDs transfer almost all consumed energy to visible light.

Why is a sunflower yellow?

It reflects yellow light.

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.

Choose the correct definition and two examples of kinetic energy.

Kinetic energy is the energy an object has due to its motion. A car driving down the highway or molecules of hot, raising up air have kinetic energy.

For the purposes of seeking a theory to explain the formation of the solar system, we identify four major features of our solar system. Which of the following represent these four major features?

Large bodies in the solar system have orderly motions. Several exceptions to the general trends stand out. Planets fall into two major categories (terrestrial and jovian). Swarms of asteroids and comets populate the solar system.

Why do we say that light is an electromagnetic wave? What is the relationship among wavelength, frequency, and speed for light?

Light is a vibration of electric and magnetic fields. ν=cλ

Why doesn't a microwave oven make a plastic dish get hot?

Microwave ovens are tuned to emit frequencies absorbed by water molecules, not by a plastic dish.

This diagram shows the approximate depths to which different wavelengths of light penetrate Earth's atmosphere. Why does it show an airplane?

Much of the infrared spectrum can be observed from an airplane that flies above most clouds.

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.

Suppose that two stars are separated in the sky by 0.1 arcsecond. Choose the correct statement describing, what will you see if you look at them with a telescope that has an angular resolution of 0.5 arcsecond.

One point of light that is the blurred image of both stars.

Which of the following procedures would allow you to make a spectrum of the Sun similar to the one shown, though with less detail?

Pass a narrow beam of sunlight through a prism.

Choose the correct definition and two examples of potential energy.

Potential energy is energy that is stored. Two examples are mechanical energy in a compressed spring and gravitational energy in a rock on the top of a hill.

Choose the correct definition and two examples of radiative energy.

Radiative energy is energy in the form of light. Sunlight and radio waves carry this form of energy.

Home satellite dishes (such as those used for television) receive signals from communications satellites. Why do these satellites must be in geostationary orbit?

Satellite dishes do not have to track position of a geostationary satellite.

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.

Why do some clay dishes get hot in the microwave?

Some clay dishes contain some water inside them.

This x-ray image was taken by the Chandra X-ray Observatory. Without knowing anything more about the object that is shown, what can you conclude from looking at this image?

Some parts of the object emit more x-rays than others.

The diagram represents energy levels in a hydrogen atom. The labeled transitions (A through E) represent an electron moving between energy levels. If an electron at level 1 in a hydrogen atom absorbs 10.2 eV of energy, it moves to level 2. What typically happens next?

The electron returns to level 1 by emitting an ultraviolet photon with 10.2 eV of energy.

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.

Which of the following best describes why the Sun's spectrum contains black lines over an underlying rainbow?

The Sun's hot interior produces a continuous rainbow of color, but cooler gas at the surface absorbs light at particular wavelengths.

The "extraordinary" part of Comte's claim was his statement that we could never learn the composition of stars. Which of the following best summarizes the key lesson we should learn from the fact that his claim was ultimately proven wrong?

The advance of science and technology may someday provide ways to answer questions that seem unanswerable today.

Consider only the first major feature, which concerns observed patterns of motion in the solar system. Scientifically, which of the following possible conclusions is justified from the patterns of motion alone?

The planets were not each born in a separate, random event.

Would the order of the ranking for the different forms of light listed in Part A be different if you were ranking the frequency of the different forms of light (lowest to highest, left to right)? What if the ranking is done for the wavelengths of the different forms of light (shortest to longest, left to right)?

The ranking by frequency would have the same order, since energy is directly proportional to frequency. The ranking by wavelength would have the opposite order, because frequency and wavelength are inversely related.

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.

Choose the correct explanation why does the following statement make sense (or is clearly true) or does not make sense (or is clearly false): "I've never been to space, so I've never experienced weightlessness."

The statement does not make sense. Any person can experience weightlessness on Earth, it just requires long enough free-fall.

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?

The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

This photo shows a single star photographed by the Hubble Space Telescope. Why doesn't the star appear as a single, sharp point of light?

The wave properties of light make this type of blurring an unavoidable feature of any telescope.

Choose the correct conditions, under which two atoms are different isotopes of the same element.

Two atoms having the same number of protons and different numbers of neutrons.

What do we mean when we say that energy levels are quantized in atoms?

We mean that the electrons can have only discrete values of electrical potential energy in atoms.

Notice that the Sun's spectrum appears brightest (or most intense) in the yellow-green region. This fact tells us __________.

the approximate temperature of the Sun's surface

Could such a reactor power the entire United States with the water flowing from your kitchen faucet? Assume that it takes you 15 seconds to fill the 1.5-liter kettle.

Yes, and it would even have energy to spare.

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.

Suppose you have a camera attached to a telescope, and you want to record an image of a faint galaxy. Which of the following will help the most?

a lot of pixels and a long exposure time

Study the graph of the intensity of light versus wavelength for continuous spectra, observing how it changes with the temperature of the light bulb. Recall that one of the laws of thermal radiation states that a higher-temperature object emits photons with higher average energy (Wien's law). This law is illustrated by the fact that for a higher temperature object, the graph peaks at __________.

a shorter wavelength

If you heat a rock until it glows, its spectrum will be:

a thermal radiation spectrum.

Which technology can allow a single ground-based telescope to achieve images as sharp as those from the Hubble Space Telescope?

adaptive optics

Compared to red light, blue light has higher frequency,

higher energy, and shorter wavelength.

Where should you put a telescope designed for ultraviolet observations?

in Earth orbit

Some nitrogen atoms have seven neutrons and some have eight neutrons; these two forms of nitrogen are

isotopes of each other.

If you see the color red in an X-ray image from the Chandra X-Ray Observatory, it means:

it depends: the colors are chosen arbitrarily to represent something about the X rays recorded by the telescope.

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

In the illustration of the solar spectrum, the upper left portion of the spectrum shows the __________ visible light.

lowest frequency

If you wanted a radio telescope to achieve the same angular resolution as a visible-light telescope, it would need to be:

much larger.

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

one-quarter as strong.

The Cassini spacecraft:

orbited Saturn.

A spectral line that appears at a wavelength of 321 nmnm in the laboratory appears at a wavelength of 328 nmnm in the spectrum of a distant object. We say that the object's spectrum is:

redshifted.

When your eye forms an image, the _____ plays a role analogous to the detector in a camera.

retina

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

Any particular location on Earth experiences __________.

two high tides and two low tides each day

Compared to an atom as a whole, an atomic nucleus is

very tiny but has most of the mass.