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3 years ago

A sound wave traveling downward with a speed of about 4,000 m/s suddenly slows to 1,500 m/s not far below the Earth’s surface.

Physics

2 answers:

WINSTONCH [101]3 years ago

5 0

Speed of sound wave depends on the elasticity of medium

It is given by formula

$v = \sqrt{\frac{E}{\rho}}$

now if we are given that initially sound wave is travelling with speed 4000 m/s

Then its speed becomes 1500 m/s

so here since speed is decreased by large value

so here elasticity must decreased by large amount

A. a different kind of rock

B. an underground lake

C. an open cavity

D. a pile of dinosaur bones

So in above all options the density is changed or decreased by large value if the medium is changed to solid to liquid

So the correct answer will be

<em>B. an underground lake </em>

alexira [117]3 years ago

4 0

Answer: An underground lake

Hope that helped :D

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Determine which heat transfers below are due to the process of conduction. I) You walk barefoot on the hot street and it burns y

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I) You walk barefoot on the hot street and it burns your toes.

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Just like in the previous example, the hot leather is in direct contact with your skin (I guess if you're going to drive naked). Thermal energy from the leather will transfe to your skin, then to the rest of your body. This is also conduction.

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IV) A boy sits to the side of a campfire. He is 10 feet away, but still feels warm.

The campfire heats air directly nearby. The warm air expands and moves away from the fire in all directions, leaving behind unheated, denser air to be heated up. Some of the warm air reaches the boy. This is another example of convection.

The answer is A) 1 and 2.

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3 years ago

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What is gravity’s role in tides?

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You observe two cars traveling in the same direction on a long, straight section of Highway 5. The red car is moving at a consta

Arte-miy333 [17]

Answer:

1) 3.66 s

2) 124.44 m

3) 3.12 s

Explanation:

Let's start by first listing down the information in the question.

Red Car : 34 m/s

Blue Car: 28 m/s

Distance between them : 22 m

The difference in speed between the cars is: 34 - 28 = 6 m/s

This means that the red car is catching up to the blue car at a speed of 6 m/s.

1) We can solve this by just dividing the distance by the difference in speed. This becomes: $\frac{Distance}{Speed}= \frac{22}{6} = 3.66$

Thus it takes 3.66 seconds for the red car to catch up to the blue car.

2) We know from (1) that it took 3.66 seconds for the red car to catch up. Since the speed it was travelling at is constant, we only need to multiply it by the time from (1) to get the distance.

This becomes: $Speed * Time = 34 * 3.66 = 124.44$

Thus the red car travels 124.44 m before catching up to the blue car.

3) If the red car starts to accelerate the moment we see it, the time taken to get to the blue car will be less than before. We can find this in a simple way.

We can use the motion equation : $s = u*t + \frac{1}{2}(a * t^2)$

Here s = 22 m

We can take u as the difference in speed. u = 6 m/s

Acceleration a = (2/3) m/s^2

Substituting the these into the equation we get:

$22 = 6t + \frac{1}{2}(\frac{2}{3}t^2)$

Solving this for the variable 't' using the quadratic formula we get the following two answers:

t1 = 3.12 s

t2 = - 21.12 s

Since t2 is not possible, the answer is t1. This means it takes 3.12 seconds for the red car to catch up to the blue.

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PLEASE HELP I need the answer to this question ASAP

cestrela7 [59]

Answer:

answer is A

Explanation:

hope this helps!

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