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.
1) 3 miles/Hour
The speed is defined as the distance covered divided by the time taken:
where
d = 1.5 mi is the distance
t = 0.5 h is the time taken
Substituting,
2) 1.34 m/s south
Velocity, instead, is a vector, so it has both a magnitude and a direction. We have:
is the displacement in meters
is the time taken in seconds
Substituting,
And the direction of the velocity is the same as the displacement, so it is south.
Answer:
0.0018 W/m²
Explanation:
Power and intensity are related as:
P= 20.0 W (given)
r = 30.0 m (given)
Intensity in decibels:
Answer:In the case of burning wood, stored potential energy (in the form of chemical energy) in the log is released due to heating by other excited atoms. This chemical reaction is called combustion and requires oxygen. Combustion changes the potential chemical energy into kinetic energy in the form of heat.
Explanation:
I don't know what you mean when you say he "jobs" the other ball, and the answer to this question really depends on that word.
I'm going to say that the second player is holding the second ball, and he just opens his fingers and lets the ball <u><em>drop</em></u>, at the same time and from the same height as the first ball.
Now I'll go ahead and answer the question that I've just invented:
Strange as it may seem, <em>both</em> balls hit the ground at the <em>same time</em> ... the one that's thrown AND the one that's dropped. The horizontal speed of the thrown ball has no effect on its vertical acceleration, so both balls experience the same vertical behavior.
And here's another example of the exact same thing:
Say you shoot a bullet straight out of a horizontal rifle barrel, AND somebody else <em>drops</em> another bullet at exactly the same time, from a point right next to the end of the rifle barrel. I know this is hard to believe, but both of those bullets hit the ground at the same time too, just like the baseballs ... the bullet that's shot out of the rifle and the one that's dropped from the end of the barrel.
