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pshichka [43]
2 years ago
15

___________ are over 500 million years old and have been developing their unique system all that time.

Physics
2 answers:
Varvara68 [4.7K]2 years ago
5 0

Answer:

none the earth isn't that old

Explanation:

zhannawk [14.2K]2 years ago
3 0

Answer:

C

Explanation:

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Where does matter come from?
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The Big Bang theory is matter and energy in the universe exploded out from one point. As the explosion occurred, energy and matter spread outward and formed the universe. The matter from the Big Bang formed clouds of gas.
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2 years ago
A loudspeaker in a parked car is producing sound whose frequency is 20 510 Hz. A healthy young person with normal hearing is sta
Vsevolod [243]

Answer:

The car must be moving away from the person.

Explanation:

From Doppler's Effect, we know that when a sound source moves towards a stationary observer, the apparent frequency of that sound increases. While the apparent frequency decreases if the source moves away from the stationary observer.

The audible range of frequencies for a human ear is 20 Hz to 20000 Hz. Therefore, in order for the sound of a loud speaker to be audible for the person, the frequency must decrease below 20000 Hz.

<u>Due to this reason, the car must be moving away from the person.</u>

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The sun is located in
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Milky Way Galaxy, same one as you.
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2 years ago
Read 2 more answers
Tina is driving her sports car down US1, traveling 27m/s. She sees her friend Rita up ahead, waiting to cross the street at the
mrs_skeptik [129]

Answer:

434 Hz

Explanation:

According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.

In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.

The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.

3 0
2 years ago
6. Aaron will run from home at y mph and walk back at x mph. how much distance does he need to travel to spend a total of t hour
Kisachek [45]

Answer:

Total distance, d=\dfrac{xyt}{(x+y)}

Explanation:

It is given that,

Speed of Aaron from home is y mph and walk back at x mph. Let t is the total time he spend in walking and jogging. Let d is the distance covered.

We he moves from home to destination, time is equal to, \dfrac{d}{x}

Similarly, when he move back to home, time taken is equal to \dfrac{d}{y}

Total time taken is equal to :

\dfrac{d}{x}+\dfrac{d}{y}=t

d(\dfrac{1}{x}+\dfrac{1}{y})=t

d=\dfrac{t}{(\dfrac{1}{x}+\dfrac{1}{y})}

d=\dfrac{xyt}{(x+y)}

So, the distance he speed in walking and jogging is \dfrac{xyt}{(x+y)}. Hence, this is the required solution.

8 0
3 years ago
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