ASTR 263 Chapter 4.4-5.3

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?

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

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.

Choose the correct definition of electrical charge.

Electrical charge is a measure of how strongly something will interact with electromagnetic fields.

Why is Newton's version of Kepler's third law so useful to astronomers?

It can be used to determine the masses of many distant objects.

Which statement must be true in order for a rocket to travel from Earth to another planet?

It must attain escape velocity from Earth.

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.

Approximately where is it currently high tide on Earth?

On the portion of Earth facing directly toward the Moon and on the portion of Earth facing directly away from the Moon.

Earth has two tidal bulges at all times. Approximately where are these bulges located?

One faces the Moon and one faces opposite the Moon.

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.

Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond?

They have a frequency of 2 hertz.

Which of the following best describes the fundamental difference between two different chemical elements (such as oxygen and carbon)?

They have different numbers of protons in their nucleus.

There are more atoms in a glass of water than stars in the observable universe.

True

Choose the correct explanation of an electron and a proton or two electrons attracting or repelling one another.

We define a proton as having +1 unit of charge and an electron as having -1 unit when talking about atoms and particles. Two particles with charges of different sign will attract each other, so protons and electrons will attract. Particles with charges of the same sign will repel each other, so two electrons will repel each other.

Choose the correct description of what do we mean when we say that light is an electromagnetic wave and the relationship among wavelength, frequency, and speed for light waves.

We say that light is an electromagnetic wave because light is a oscillation of electric and magnetic fields. frequency= speed of light / wavelength

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.

Radio waves are:

a form of light

At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter?

a plasma consisting of positively charged ions and free electrons

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

According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them _________.

decreases by a factor of 9

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

gravitational potential energy being converted to thermal energy

Compared to red light, blue light has higher frequency and

higher energy and shorter wavelength than red light.

Which forms of light are lower in energy and frequency than the light that our eyes can see?

infrared and radio

As a gas cloud shrinks in size, its rate of rotation speeds up because

its total angular momentum is conserved.

Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon?

its wavelength and energy

Red light has a _____ wavelength and a _____ frequency than does blue light.

longer, lower

Vaporization is the process in which

molecules go from the solid phase to the gas phase.

Suppose that you had "X-ray vision" that allowed you to see X rays. What would you notice when you looked at a friend standing near you that you could not notice with your visible light vision alone?

nothing

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

one-quarter as strong.

If you have a telescope that is observing light with wavelengths of a few meters, you are observing __________.

radio waves

X ray photons have a _____ wavelength, _____ frequency, and _____ energy than do ultraviolet photons.

shorter, higher, higher

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

As a gas cloud collapses, the overall force of gravity that draws the cloud inward gradually becomes stronger because

the strength of gravity follows an inverse square law with distance

Any particular location on Earth experiences __________.

two high tides and two low tides each day