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3 years ago

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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What is the mass of a ball that has 29j of potential energy and is lifted 2.0m?

Salsk061 [2.6K]

Answer:

1.48kg

Explanation:

Here,

potential energy (P.E) = 29j

height (h) = 2m

acceleration due to gravity(g) =

$9.8m {s}^{ - 2}$

mass(m) = ?

we know,

P.E = mgh

or, 29 = m×9.8×2

or, 29/19.6 = m

or,m = 1.48kg

6 0

2 years ago

Find the mass of a football player who has 1420 N of force and an acceleration of 4 m/s^2 *

Hatshy [7]

The answer is 833.3 kg

7 0

3 years ago

6. What is the change in temperature of a metal rod that is 55.0 cm long, decreases length by 0.20 cm, and that has a coefficien

MrMuchimi

Explanation:

We have,

Length of a metal rod is 55 cm or 0.55 m

Change in length is 0.2 cm or 0.002 m

It is required to find the change in temperature of a metal rod. The coefficient of linear expansion is given by :

$\alpha =\dfrac{\Delta L}{L_0\Delta T}$

$\Delta T$ is the change in temperature

$\Delta T =\dfrac{\Delta L}{L_0\alpha }\\\\\Delta T =\dfrac{0.002}{0.55\times 12\times 10^{-6}}\\\\\Delta T= 303.03^{\circ} C$

So, the change in temperature is 303.03 degrees Celsius.

4 0

3 years ago

How does the sun rise and set

MatroZZZ [7]

Answer:

c. earth rotates on it tilted axis and orbit around the sun at the same time

Explanation:

Earth rotation can be defined as the amount of time taken by planet earth to complete its spinning movement on its axis.

This ultimately implies that, the rotation of earth refers to the time taken by earth to rotate once on its axis. One spinning movement of the earth on its axis takes approximately 24 hours to complete with respect to the sun. Thus, this makes us to experience day and night (sun rise and sun set) due to the rotation of planet about its axis.

Hence, the sun rise and set because the earth rotates on it tilted axis and orbit around the sun at the same time

8 0

3 years ago

When you get into a car with hot black leather in the middle of the summer and it hurts your skin whe you sit this is an example

NeTakaya

C.the heat is conducted to your skin

3 0

3 years ago

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