Answer:
<em>The comoving distance and the proper distance scale</em>
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Explanation:
The comoving distance scale removes the effects of the expansion of the universe, which leaves us with a distance that does not change in time due to the expansion of space (since space is constantly expanding). The comoving distance and proper distance are defined to be equal at the present time; therefore, the ratio of proper distance to comoving distance now is 1. The scale factor is sometimes not equal to 1. The distance between masses in the universe may change due to other, local factors like the motion of a galaxy within a cluster. Finally, we note that the expansion of the Universe results in the proper distance changing, but the comoving distance is unchanged by an expanding universe.
Answer:
I think the answer is b am sorry if it is wrong
Explanation:
Hello!
We can use the kinematic equation:

a = acceleration (m/s²)
vf = final velocity (45 m/s)
vi = initial velocity (25 m/s)
t = time (5 sec)
Plug in the givens:

Its because the molecules in the solid structures are very close to each other and rigidly packed, thus due to this quantum structure they have pretty awesome speed of sound in them
Answer:
16 2/3 hr
Explanation:
250 000 km / 15 000 km/hr = 16 2/3 hours