Mastery Astronomy Assign 3-Chapters 4&5

Match the words in the left-hand column to the appropriate blank in the sentences in the right-hand column. Use each word only once.

Q&A Below

The animation 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 drawing the cloud inward __________ because __________.

*(Blank 1) gradually becomes stronger *(Blank 2) the strength of gravity follows an inverse square law with distance

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

*(Blank 1) increases *(Blank 2) gravitational potential energy being converted to thermal energy

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

*(Blank 1) speeds up *(Blank 2) its total angular momentum is conserved

1. The light from Polaris travels through space in the form of _______ energy. 2. Rapidly moving comets have more _____ energy than slowly moving ones. 3. An apple contains ______ energy that your body can convert into other forms energy. 4. Nuclear fusion in stars converts some of the _____-energy of hydrogen nuclei into light and heat. 5. Due to its much higher density, water heated to 80 degrees (Celsius) contains more ______ energy than air at the same temperature. 6. An asteroid that is moving farther from the Sun is gaining ______________ energy.

1. radiative 2. kinetic 3. chemical potential 4. mass 5. thermal 6. gravitational potential

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 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.

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.

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

They should be much smaller compared to Earth.

Listed following are various physical situations that describe how light interacts with matter. Match these to the appropriate category.

Transmission: *visible light meets clear glass *cell phone signals pass through walls Absorption: *blue light hits a red sweatshirt *visible light does not pass through a black wall Reflection or Scattering: *red light hits a red sweatshirt *white light hits a white piece of paper Emission: light comes from a light bulb *light comes from your computer screen

According to the laws of thermal radiation, hotter objects emit photons with _________.

a shorter average wavelength

What time is it at point 1?

cannot be determined from the information in the figure.

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

chemical composition

A star whose spectrum peaks in the infrared is:

cooler than our 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

The gravitational potential energy of a contracting interstellar cloud

gradually transforms into other forms of energy.

Compared to red light, blue light has higher frequency and

higher energy and shorter wavelength.

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

infrared and radio

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

is very tiny but has most of the mass.

Where is it high tide?

points 1 and 3

Where is it low tide?

points 2 and 4

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

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.