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nataly862011 [7]
3 years ago
5

Laboratory experiments here on Earth have determined that each element in the periodic table emits photons only at certain wavel

engths. These photons are apparent to astronomers as either emission or absorption lines in the spectrum of an astronomical object, like stars in galaxies. Astronomers can, by measuring the position of these spectral lines, determine which elements are present in the star itself or along the line of sight. When astronomers perform this analysis, they note that for most astronomical bodies, the observed spectral lines are all shifted to longer (redder) wavelengths. This is known as cosmological redshift and is analogous to the Doppler redshift. What does this redshift indicate to us about the universe in general?
Physics
1 answer:
elena-14-01-66 [18.8K]3 years ago
7 0
The only thing we know about so far that can shift wavelengths of light
to longer wavelengths is when the source of the light is moving away
from the observer.

When we look at the light from distant galaxies, the light from them is
always shifted to longer wavelengths than it SHOULD have. 

AND ... The farther away from us a galaxy IS, the MORE its light is
shifted to wavelengths longer than it should have.

So far, this indicates to us that the whole universe is expanding.
That's the only way to understand what we see, because that's
the only thing we know of that can shift light to longer wavelengths.


By the way ... The most interesting thing about these observations
and measurements is:  When astronomers see this light from distant
galaxies and measure the wavelengths, how do they know how far
the wavelengths shifted ?  How do they know what the wavelengths
SHOULD be ?
 
I'll leave you to read about that in the next few years.
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(HELP ASAP) A student’s cell phone battery is almost dead, and she plugs it into an electrical outlet to charge. As it charges,
Leokris [45]

Explanation:

The total energy of the system remains conserved. It just converts from one form of energy to another.

The battery of the cell phone contains chemicals. As the electricity is passed through the cell phone, the electrical energy is converted to chemical energy. As she notices that the phone is warm and after the battery has been fully charged and the student unplugs her cell phone, the phone vibrates when a message arrives, this shows the conversion of chemical energy to mechanical energy, thermal energy etc.

Hence, we can say that the correct option is (b).

6 0
3 years ago
The diver on the diving board is 10 meters high and has a mass of 0.050kg, what is his GPE?
sveta [45]

Answer:

<h2>4.9 J</h2>

Explanation:

The gravitational potential energy of a body can be found by using the formula

GPE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 9.8 m/s²

From the question we have

GPE = 10 × 9.8 × 0.05

We have the final answer as

<h3>4.9 J</h3>

Hope this helps you

6 0
3 years ago
What is a descriptions of an animal cell's nucleus?
Marat540 [252]
<span>The nucleus controls many of the functions of the cell(by controlling protein synthesis) and contains DNA (in chromosomes). The nucleus is surrounded by the nuclear membrane. ribosome - small organelles composed of RNA-rich cytoplasmic granules that are sites of protein synthesis.</span>
5 0
3 years ago
What is the speed of sound in air at 40°C?
Blababa [14]
343 meters per second Is the answer
4 0
3 years ago
Read 2 more answers
so I know you can solve this either by using Vox or Voy. I'm getting 3.08s when using Vox and 3.14s for Voy way. For Voy I'm usi
Tatiana [17]

The person's horizontal position is given by

x=v_0\cos40^\circ t

and the time it takes for him to travel 56.6 m is

56.6\,\mathrm m=\left(24.0\,\dfrac{\mathrm m}{\mathrm s}\right)\cos40^\circ t\implies t=3.08\,\mathrm s

so your first computed time is the correct one.

The question requires a bit of careful reading, and I think there may be a mistake in the problem. The person's vertical velocity v_y at time t is

v_y=v_{0y}-gt

which tells us that he would reach the ground at about t=3.15\,\mathrm s. In this time, he would have traveled

x=v_{0x}(3.15\,\mathrm s)=57.9\,\mathrm m

But we're told that he is caught by a net at 56.6 m, which would mean that the net cannot have been placed at the same height from which he was launched. However, it's possible that the moment at which he was launched doesn't refer to the moment the cannon went off, but rather the moment at which the person left the muzzle of the cannon a fraction of a second after the cannon was set off. After this time, the person's initial vertical velocity v_{0y} would have been a bit smaller than \left(24.0\,\frac{\mathrm m}{\mathrm s}\right)\sin40^\circ.

7 0
2 years ago
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