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lora16 [44]
3 years ago
14

Dois carros, a e b, móveis se em uma estrada retilínea com volocidade constante,vª =20m/s e v=18 m/s , respectivamente. O carro

A ,está, inicialmente, 500m atrás do carro B . Quanto tempo o carro A levará para alcançar o carro B?
Physics
1 answer:
LekaFEV [45]3 years ago
4 0
I just need some points
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A large fraction of the ultraviolet (UV) radiation coming from the sun is absorbed by the atmosphere. The main UV absorber in ou
irakobra [83]

Answer:

λ = 3.2 x 10⁻⁷ m = 320 nm

Explanation:

The relationship between the velocity of electromagnetic waves (UV rays) and the their frequency is:

v = fλ

where,

v = c = speed of the electromagnetic waves (UV rays) = speed of light

c = 3 x 10⁸ m/s

f = frequency of the electromagnetic waves (UV rays) = 9.38 x 10¹⁴ Hz

λ = wavelength of the electromagnetic waves (UV rays) = ?

Therefore, substituting the values in the relation, we get:

3 x 10⁸ m/s = (9.38 x 10¹⁴ Hz)(λ)

λ = (3 x 10⁸ m/s)/(9.38 x 10¹⁴ Hz)

<u>λ = 3.2 x 10⁻⁷ m = 320 nm</u>

So, the radiation of <u>320 nm</u> wavelength is absorbed by Ozone.

3 0
3 years ago
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What causes clouds of dust and gas to form a protostar
just olya [345]
<h2>Answer: Gravitational attraction </h2>

Gravity force causes the clouds of dust and gas to form a protostar. As this <u>attraction force</u> is responsible for gathering and compressing the existing elements in the cloud of gas and dust, heating them during this process.

Then, when the amount of material accumulated by gravitational contraction is large enough, and the temperature and pressure reached high enough, the <u>nuclear fusion</u> process will begin.

To understand it better: The hydrogen nuclei will begin to fuse, generating helium nuclei in the process and releasing huge amounts of energy.

It should be noted that the protostars radiate half of the energy contributed by the gravitational collapse and the other half is invested in heating its core.

4 0
3 years ago
A basketball is tossed up into the air, falls freely, and bounces from the wooden floor. From the moment after the player releas
Tju [1.3M]

Answer:

Tha ball- earth/floor system.

Explanation:

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3 years ago
Which of the following is not a part of the SMART acronym? Question 5 options: Specific Measurable Respectable Time-bound
juin [17]

The answer is Respectable

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3 years ago
Select all that apply to electrons and energy levels. - Scientists have not yet determined exactly why electrons do not collapse
Elenna [48]

Answer:

- The limitation of the maximum number of electrons in a given energy level can be used to account for the periodic recurrence of properties as the number of electrons increases.

Explanation:

First - Scientists have not yet determined exactly why electrons do not collapse into the nucleus. FALSE: Scientists do know why electrons do not collapse. Since the beginins of quantum mechanics it's known that the energy at small scales is quantized, that means there only can be certain values meaning that the energy do not change continously. In the case of the electron, it can only have certain levels of energy, that means they do not radiate continously as the go arround the atom, instead it is only allowed to have a certain amount of energy in a given state therefore it can not lose energy continously collapsing into the nucleus.

Second - Electrons cannot be located between levels except when they are in the process of moving. FALSE: We can not say that a electron moves between energy levels, it only can exist in any of the levels, but never in between. Also, the electron in any of its possible energy lavels can not be located with complete certainty due to the uncertainty principle.

Fourth - Electrons have any random energy. FALSE:  as exposed above the electrons can only have certain cuantized energy levels acordinly to the rules of quantum physics

Fifth - Electrons can be found between energy levels. FALSE: Like said before we can not say that a electron exists between energy levels, it only can exist in any of the allowed levels, but never in between.

Thirth (correct one) :  - The limitation of the maximum number of electrons in a given energy level can be used to account for the periodic recurrence of properties as the number of electrons increases. TRUE: the maximum number of electrons allowed in a given energy level directly determines the tipe of bond an atom can made with another (this due to the number of electrons in the higest energy level), so for example the elements in the left of a given row of the periodic table tend to have ionic bonds, but in the other hand the elements on right side tend form more covalent bonds. And this characteristic directly correllate with diferent properties of the elements.

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3 years ago
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