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Solnce55 [7]
3 years ago
13

Important changes in the musculoskeletal system due to physical activity seem to begin at _______ minutes of activity a week. A.

30 B. 60 C. 80 D. 90
Physics
1 answer:
baherus [9]3 years ago
5 0
I think the answer is a
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A spacecraft is moving past the earth at a constant speed of 0.60 times the speed of light. The astronaut measures the time inte
Afina-wow [57]

Answer:

the time interval that an earth observer measures is 4 seconds

Explanation:

Given the data in the question;

speed of the spacecraft as it moves past the is 0.6 times the speed of light

we know that speed of light c = 3 × 10⁸ m/s

so speed of spacecraft v = 0.6 × c = 0.6c

time interval between ticks of the spacecraft clock Δt₀ = 3.2 seconds

Now, from time dilation;

t = Δt₀ / √( 1 - ( v² / c² ) )

t = Δt₀ / √( 1 - ( v/c )² )

we substitute

t = 3.2 / √( 1 - ( 0.6c / c )² )

t = 3.2 / √( 1 - ( 0.6 )² )

t = 3.2 / √( 1 - 0.36 )

t = 3.2 / √0.64

t = 3.2 / 0.8

t = 4 seconds

Therefore, the time interval that an earth observer measures is 4 seconds

6 0
3 years ago
What is the 5 quantitative research problems?<br>​
iogann1982 [59]

Answer:

There are four main types of Quantitative research: Descriptive, Correlational, Causal-Comparative/Quasi-Experimental, and Experimental Research. attempts to establish cause- effect relationships among the variables. These types of design are very similar to true experiments, but with some key differences.

Explanation:

Quantitative research is defined as a systematic investigation of phenomena by gathering quantifiable data and performing statistical, mathematical, or computational techniques.

<h3>I hope it will help you</h3>

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7 0
2 years ago
What are carbon-12, carbon-13, and carbon-14?
Jet001 [13]
The answer would be C. (:
6 0
2 years ago
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What is the meaning of the word solar in the article "Fire Up the Sun"?
SpyIntel [72]

Answer:

B) Caused by the Sun

Explanation:

If you look at a picture of a solar system, you will see the sun in the middle. The sun is the powerhouse of the solar system. So that means that the sun is the biggest star and can provide enough light to reach earth and keep it lit.

4 0
2 years ago
Thomson's cathode ray beam bent towards the positively charged plate. With this information, he was able to conclude
andre [41]
I believe the correct answer from the choices listed above is the second option. With this information, he was able to conclude that the beam was negatively charged. His cathode ray<span> tube experiments led to a very important scientific discovery, the electron. Hope this answers the question.</span>
8 0
3 years ago
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