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yulyashka [42]
3 years ago
5

How can astronomers infer approximately how long the universe has been expanding?

Physics
2 answers:
Oksi-84 [34.3K]3 years ago
8 0

Answer:

Explanation:

As we know that universe is not constant, it is expanding from a very long time.

Scientist and astronomers have been working for a very long time to know the age of universe and for how long it has been expanding. This can be determined by  calculating the age of rocks and objects found in universe.

The decay rate and the emission of radioactive elements also give us information about the expansion of universe.

The expansion rate can also be determined by a number called as hubble constant. Astronomers determine the regulation of dark energy.

A low density matter in universe is older, hence all these factors tells us about the expansion of universe and its age.

Jlenok [28]3 years ago
3 0
Not only astronomers, but all scientists use the technique of rock dating to determine the age of the universe. From the Big Bang Theory, all the celestial bodies were made at the same time. So, the age of the Earth is just the same with the age of the universe. So, they gather rocks deep down in the crust of the Earth and let it undergo radioactive decay. By determining the amount of radioactive material left and half-life, they could compute the age of the Earth.
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Mamie clark was a psychologist who is known for her research on ?
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Mamie Phipps Clark is a noted woman psychologist, best known for her research on race, self-esteem, and child development. Her work alongside her husband, Kenneth Clark, was critical in the 1954 Brown vs Board of Education case and she was the first black woman to earn a degree from Columbia University.

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3 years ago
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At the train station, you notice a large horizontal spring at the end of the track where the train comes in. This is a safety de
e-lub [12.9K]

Assume a maximum stopping acceleration of g/2 where g is acceleration due to gravity.

Answer:

2.99 m/s

Explanation:

Stopping distance, s = 3 ft = 0.914 m

final velocity, v = 0

a = g/2 = 4.9 m/s²

Use third equation of motion:

v^2-u^2 = 2as

substitute the values to find the speed of train:

0 -u^2 = 2\times -4.9 \times 0.914 \\u^2=8.96 \\u=2.99 m/s

6 0
4 years ago
Compared to the cells in a healthy body, Elisa’s cells are getting far fewer ____________________ molecules.
Elenna [48]

Answer:

glucose

Explanation:

7 0
3 years ago
Here's a basketball problem: A 87.2 kg basketball player is running in the positive direction at 7.0 m/s. She is met head-on by
Ray Of Light [21]

Answer:

2.47 m/s backwards

Explanation:

From the law of conservation of momentum,

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂...................... Equation 1

Where m₁ and m₂ = mass of the first basketball player and second basket ball player respectively, u₁ and u₂ = initial velocity of the first basket player and the second basketball player respectively, v₁ and v₂ = The final velocity of the first basket ball player and second basket ball player respectively.

Making v₁ the subject of the equation,

v₁ = (m₁u₁ + m₂u₂ - m₂v₂)/m₁.......................... Equation 2.

Given: m₁ = 87.2 kg, m₂ = 102.0 kg, u₁ = 7.0 m/s, u₂ = -5.2 m/s, v₂ = 2.9 m/s

Note: u₂ is negative because it moves towards the first basket ball player.

Substitute into equation 2

v₁ = [87.2(7.0)+102(-5.2) - (102×2.9)]/87.2

v₁ = (610.4-530-295.8)/87.2

v₁ = -215.4/87.2

v₁ = -2.47 m/s.

Thus the velocity of the 87.2 kg player = 2.47 m/s backwards.

7 0
4 years ago
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