1 and A
2 and B
3 and D
4 and C
Explanation:
The angular momentum is doubled because it is proportional to the angular velocity.
(a) The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
(b) The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
<h3>
What is interstellar medium?</h3>
Interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy.
<h3>Evidence that interstellar medium contains both gas and dust</h3>
- The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
- The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
Learn more about interstellar medium here: brainly.com/question/4173326
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The speed of the spaceship relative to the galaxy is 0.99999995c.
A light-year measures distance rather than time (as the name might imply). A light-year is a distance a light beam travels in one year on Earth, which is roughly 6 trillion miles (9.7 trillion kilometers). One light-year equals 5,878,625,370,000 miles. Light moves at a speed of 670,616,629 mph (1,079,252,849 km/h) in a vacuum.We multiply this speed by the number of hours in a year to calculate the distance of a light-year (8,766).
The Milky way galaxy is 100,000 light years in diameter.
The galaxy's diameter is a mere 1. 0 ly.
We know that ;

L = 1 light year
L₀ = 100,000 light year




Therefore, the speed of the spaceship relative to the galaxy is 0.99999995c.
Learn more about a light year here:
brainly.com/question/17423632
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Answer:

Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:

where these are the masses are initial velocities of both players.
After the collision we have:

since they clong together, acting as one body.
This means we have:

Or:

Which for our values is:
