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denis-greek [22]
2 years ago
8

If the average density of the Universe is small compared with the critical density, the expansion of the Universe described by H

ubble's law proceeds with speeds that are nearly constant over time. (a) Prove that in this case the age of the Universe is given by the inverse of the Hubble constant.
Physics
1 answer:
Ratling [72]2 years ago
7 0

(a) v=HR defines the Hubble constant. According to R=vt, the gap R between any two far-separated objects opens at a constant speed. The time interval t since the Big Bang is then calculated.

v=HvΔt→Δt=\frac{1}{H}

<h3>What exactly is the Hubble constant?</h3>

  • Hubble constant, in cosmology, a proportionality constant in the relationship between the velocities of distant galaxies and their distances.
  • It expresses the rate of expansion of the universe. It is represented by the symbol H_{0}, with the subscript indicating that the value is measured at the present time, and is named after Edwin Hubble, an American astronomer who attempted to measure its value in 1929.
  • Hubble established the cosmological velocity-distance law using redshifts of distant galaxies measured by Vesto Slipher, also of the United States, and his own distance estimates for these galaxies:
  • H_{0} distance = velocity

To learn more about Hubble constant refer to

brainly.com/question/26117248

#SPJ4

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Give a calculate answer to show that the two values (English system and metric system) for the Planck Constant are equivalent.
Nataly_w [17]

Answer:

Given values of Planck Constant are equivalent in English system and metric system.

Explanation:

Value of Planck's constant is given in English system as 4.14 x 10⁻¹⁵eV s.

Converting this in to metric system .

We have 1 eV = 1.6 x 10⁻¹⁹ J

Converting

     4.14 x 10⁻¹⁵eV s = 4.14 x 10⁻¹⁵x 1.6 x 10⁻¹⁹ = 6.63 x 10⁻³⁴ Joule s

So Given values of Planck Constant are equivalent in English system and metric system.

7 0
3 years ago
Distinguish between friction force and motion?
Ksju [112]

Friction force is when you rub 2 things together and they get warm. Motion, on the other hand, is if your walking along the sidewalk - you hardly get warmer -------


Unless it's a colder day outside and you're walking SO you decide to rub your hands together to get warm, but if you were just walking , its motion and only motion - no friction :):)

6 0
3 years ago
Agustin visits Panama City, Florida, during the month of May. He feels a shore breeze blowing from theocean onto the beach. What
Pavel [41]

Answer: A.The ocean is colder than the land

Explanation:

Based on the information provided in the question, we are informed that Agustin visits Panama City, Florida, during the month of May and that he feels a shore breeze blowing from the ocean onto the beach.

The reason for the shore breeze is simply due to the fact that the ocean is colder than the land. Since the ocean is colder, anyone who goes to the beach will feel the breeze.

7 0
2 years ago
The table shows the diameters of the planets in our solar system. Assume that a basketball whose diameter is 25
tino4ka555 [31]

Answer:

Mercury:

.85

pea

Venus:

2.1

gumball

Earth:

2.2

gumball

Mars:

1.2

marble

Uranus:

9

grapefruit

Neptune:

8.6

softball

Explanation:

I have no clue if I'm right but hopefully, I am

3 0
2 years ago
A 0.02kg dart is loaded into a toy spring gun by compressing the spring 6cm. If the spring has a constant of 20 N/m, find… a. Th
katrin2010 [14]

Answer:

a) 0.036 J b) 0.036J c) 0.036 d) 1.9m/s e) 0.18 m

Explanation:

Mass of the dart = 0.02kg, the spring was compressed to 6cm

Work needed to compress the spring = 1/2*k*x ^2 where k is the force constant of the spring in N/m, x is the distance it was compressed in m

Work needed to compress the spring = 0.5 * 20* 0.06^2 since 6cm = 6 / 100 = 0.06 m

Work needed to compress the spring = 0.036J

b) the total energy stored in the spring = the work done to compress the spring = 0.036J

c) kinetic energy of the dart as it leaves the the spring = elastic potential energy stored in the spring = the work done in compressing the = 0.036J using the law of conservation of energy; energy is neither created nor destroyed but transformed from one form to another.

d) 1/2mv^2 = 0.036

mv^2 = 0.036*2

v^2 = 0.036*2 / 0.02 = 3.6

v = √3.6 = 1.897 approx 1.9m/s

e) kinetic energy of the dart = work done against gravity to get the body to height h

Work done against gravity = potential energy conserved at height = -mgh g is negative because the motion is upward while gravity acts downward

0.036 = 0.02 * 9.81 * h

0.036 / ( 0.02*9.81) = h

h = 0.18 m

6 0
3 years ago
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