Answer:
C. 98 J
Explanation:
The appropriate formula is ...
PE = mgh . . . . . m is mass; below, m is meters
PE = (5 kg)(9.8 m/s^2)(2 m) = 98 kg·m^2/s^2
PE = 98 J
Answer:
I don’t understand Espanol
Explanation:
sorry
Answer:
red shift, indicating that the universe is expanding
Explanation:
Doppler effect occurs when a source of a wave (e.g. light, or sound waves) moves relative to an observer; as a result of this relative motion, the wavelength of the wave appears lengthened/shortened to the observer. Two situations can occur:
- The source of the wave is moving towards the observer - in this case, the wavelength of the wave becomes shorter. If the wave is visible light, such as the light emitted by distant galaxies, this means that the wavelength of the light shifts towards the blue-end of the spectrum (blue-shift)
- The source of the wave is moving away from the observer - in this case, the wavelength of the wave becomes longer. If the wave is visible light, such as the light emitted by distant galaxies, this means that the wavelength of the light shifts towards the red-end of the spectrum (red-shift)
In our universe, we observe a red-shift for all the distant galaxies: this means that these galaxies are moving away from us, so this is an indication that the universe is expanding.
Answer:
1). 
2). Toward us
3). 
4). Toward us
5). 
6). Away from us
7). 
8). Away from us
Explanation:
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when it is moving away from the observer (that is known as the Doppler effect).
The wavelength at rest is 121.6 nm (
)
Then, for this particular case it is gotten:
Star 1: 
Star 2: 
Star 3: 
Star 4: 
Star 1:
Toward us
Star 2:
Toward us
Star 3:
Away from us
Star 4:
Away from us
Due to that shift the velocity of the star can be determine by means of Doppler velocity.
(1)
Where 
is the wavelength shift, 
is the wavelength at rest, v is the velocity of the source and c is the speed of light.
(2)
<em>Case for star 1 
:</em>
<em></em>
Notice that the negative velocity means that is approaching to the observer.
<em>Case for star 2 
:</em>
<em>Case for star 3 
:</em>
<em>Case for star 4 
:</em>
