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Dominik [7]
3 years ago
7

Kenneth observes that as an ambulance approaches him, the pitch of the sound of the siren is higher, and the pitch decreases whe

n the ambulance moves away from him. Which of the
following is the possible scientific reason for the situation?
A The wavelength of the sound wave gets shorter, and hence the pitch gets higher
B. The wavelength of the sound wave gets longer, and hence the pitch gets higher
C. The wavelength of the sound wave does not affect the pitch
D. The wavelength of the sound wave changes the speed of the wave
Physics
1 answer:
alexgriva [62]3 years ago
3 0

Answer: A.

Explanation:

Since pitch and frequency are the same thing when frequency is higher the wavelength decreases and A is the only valid answer.

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14. When incoming light rays strike a flat, plane mirror at an
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Answer:

close to the mirrors surface

Explanation:

this is because angle of incidence equals angle of reflection

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3 years ago
In your own words, explain what conservation of energy means. Also, give an example of the conservation of energy using somethin
Genrish500 [490]
Energy can not be created or destroyed but can change from one form to another.

example: as a roller coaster cart loses height the more speed it gains, the potential energy is transferred into kenetic energy
8 0
2 years ago
The critical angle between a medium and air is 430. What is the speed of light in that medium?
vagabundo [1.1K]

Answer:

The speed of light is that medium is 281907786.2 m/s.

Explanation:

since the critical angle is Фc = 430, we know that the refractive index is given by:

n = 1/sin(Фc)

  = 1/sin(430)

  = 1.06

then if n is the refractive index of the medium and c is the speed of light, then the speed of light in the medium is given by:

v = c/n

  = (3×10^8)/(1.06)

  = 281907786.2 m/s

Therefore, the speed of light is that medium is 281907786.2 m/s.

8 0
3 years ago
Please help with these questions as well! I need urgent help! I will give brainliest! God bless!
Radda [10]

6.  Since we are not sure if the person in the question is actively lifting the crate, we have to determine the downwards force of the crate due to gravity and compare it to the normal force.  

F = ma

F = (15.3)(-9.8)

F = -150N

Since the downwards force of the crate is equivalent to the normal force, it means the person is applying no force in picking up the object.  So to pick up a 150N object from scratch, you would have to exert more force than the weight of the object, so the answer is 294N.


7.  Same idea as question 2.  

First determine the weight of the object:

F = ma

F = (30)(-9.8)

F = -294N

The crate in question is not moving, so the magnitudes of the forces in the upwards and downwards direction has to equal to 0.

-294 + 150N + x = 0

x = 144N  

So the person is exerting 144 N.


10.  First find the force of block B to the right due to its acceleration:

F = ma

F = (24)(0.5)

F = 12N

So block B is moving 12N to the right relative to block A due to block A's movement to the left.  However, block A is being applied a much greater force and is moving quicker to the left than block B is moving to the right of bock A.  The force that is causing block B to experience the lower relative force to the right is because of the friction.  To find the friction:

The sum of the forces in the leftward and rightward direction for block B must equal 12N.

75 - x = 12

x = 63N

So the force of friction of block A on block B is 63N to the left.


5 0
2 years ago
PLEASE HELP it takes tsooo long! lol ima fail! please help! thanks!
Natasha_Volkova [10]

Answer:

A and c, hope i helped xx

Explanation:

4 0
3 years ago
Read 2 more answers
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