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3 years ago

Explain why a fire engine’s siren sounds lower in pitch after the fire engine passes you.

2 answers:

5 0

When a sound source is moving toward you, you hear a higher frequency than the source is putting out, and when the source is moving away from you, you hear a lower frequency than the real one. The whole process is called the Doppler effect. It works with light too.

Sedbober [7]3 years ago

3 0

Explanation:

Doppler effect: It is the phenomenon which occurs when there is relative motion between listener and source.

In this phenomenon, there is an apparent change in the frequency. There is an increase or decrease in frequency.

The frequency gets lower when the source and the listener are moving away from each other.

The frequency gets higher when the source and the listener are moving towards each other.

The pitch depends on the frequency. When the frequency increases then the pitch of the sound gets louder. When the frequency decreases then the pitch of the sound gets lower.

In the given problem, a fire engine's siren sounds lowers in pitch after the fire engine passes. Here, the source and the listener are moving away from each other. The frequency gets lower. Then, the pitch of the sound will also get lower.

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Kindly answer the question about Work and Power. Image is attached below.

natita [175]

Answer:

89600 Watts.

Explanation:

From the question given above, the following data were obtained:

Mass (m) of speedboat = 2800 Kg

Initial velocity (u) = 0 m/s

Final velocity (v) = 16 m/s

Time (t) = 8 s

Power (P) expended by the speedboat =?

Next, we shall determine the acceleration of the speedboat. This can be obtained as follow:

Initial velocity (u) = 0 m/s

Final velocity (v) = 16 m/s

Time (t) = 8 s

Acceleration (a) =?

v = u + at

16 = 0 + (a × 8)

16 = 0 + 8a

16 = 8a

Divide both side by 8

a = 16/8

a = 2 m/s²

The acceleration of the speedboat is 2 m/s²

Next, we shall determine the force exerted by the speedboat. This can be obtained as follow:

Mass (m) of speedboat = 2800 Kg

Acceleration (a) of speedboat = 2 m/s²

Force (F) of speedboat =?

F = ma

F = 2800 × 2

F = 5600 N

Finally, we shall determine the expended by the speedboat at maximum speed. This can be obtained as follow:

Force (F) of speedboat = 5600 N

Maximum velocity (v) = 16 m/s

Power (P) expended by the speedboat =?

P = F × v

P = 5600 × 16

P = 89600 Watts

Thus, the power expended by the speedboat is 89600 Watts.

4 0

3 years ago

car travels 80 meters due north in 12 seconds then the car turns around and travels 30 Mi do South in 4 seconds calculate the av

Zinaida [17]

Answer:

1) 3.1 m/s

2) 7 m/s

Explanation:

Distance due north = 80 m

Distance due south = 30 m

Distance between north and south = (80 - 30) m = 50 m

Total time = (12 + 4) sec = 16 sec

1) Average speed = 50/16 = 3.1 m/s

2) Average velocity = Total distance/total time = (80 + 30) m/16 s = 110/16 = 7 m/s

8 0

3 years ago

An electron and a proton are both released from rest, midway between the plates of a charged parallel-plate capacitor. The only

topjm [15]

Answer:

Explanation:

Let the potential difference between the middle point and one of the plate be ΔV .

electric potential energy will be lost and it will be converted into kinetic energy .

Electrical potential energy lost = Vq , where q is charge on charge particle .

For proton

ΔV× q = 1/2 M V² ( kinetic energy of proton )

where M is mass and V be final velocity of proton .

For electron

ΔV× q = 1/2 m v² ( kinetic energy of electron )

where m is mass and v be final velocity of electron . Charges on proton and electron are same in magnitude .

As LHS of both the equation are same , RHS will also be same . That means the kinetic energy of both proton and electron will be same

1/2 M V² = 1/2 m v²

(V / v )² = ( m / M )

(V / v ) = √ ( m / M )

In other words , their velocities are inversely proportional to square root of their masses .

4 0

3 years ago

A stationary boat bobs up and down with a period of 2.4 s when it encounters the waves from a moving boat.

lapo4ka [179]

It seems like the question is asking for the frequency.
Given:
Time period (T) = 2.4 sec

Frequency (f) =?

We know that the formula for frequency is:

Frequency (f) = 1/time period (T)

= 1 / 2.4 s

= 0.42 Hz. is the frequency for this problem.

8 0

3 years ago

Write a main idea statement about the nervous system.

Alisiya [41]

Answer:

The nervous system is the major controlling, regulatory, and communicating system in the body. It is the center of all mental activity including thought, learning, and memory. Together with the endocrine system, the nervous system is responsible for regulating and maintaining homeostasis.

Explanation:

6 0

3 years ago

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