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serg [7]
3 years ago
15

A fire engine is rapidly approaching you at a stop light. What happens to the frequency and pitch of the sound as the fire engin

e draws closer? The frequency increases, and the pitch decreases The frequency increases, and the pitch increases The frequency decreases, and the pitch decreases The frequency decreases, and the pitch increases
Physics
1 answer:
ValentinkaMS [17]3 years ago
7 0

Answer:

The frequency increases, and the pitch increases

Explanation:

  • Doppler's law of sound is applicable in such case when the observer or the sound source or both are moving relative to each other.
  • In such a case due to space-time constraint the waveform of the sound adjust themselves so as to obey the law of conservation of energy.

<u>The apparent frequency of the sound for the observer is given by:</u>

f_o=(\frac{s+v_o}{s+v_s} )f ....................................(1)

where:

f_o= observed frequency

f= original source frequency

s= speed of sound

v_s= speed of source relative to the observer (taken negative when approaching towards the observer and vice-versa)

v_o= speed of observer relative to the source (taken negative when moving away from the source and vice-versa)

<u>According to the given situation, eq. (1) becomes:</u>

f_o=(\frac{s}{s-v_s} )f

Since, \frac{s}{s-v_s} >1

Therefore

f_o>f

Pitch is very closely related to the frequency, it means that how fast is the amplitude of sound varying with time.

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Answer:

The change in energy of the gas during the process is -1.83\times 10^{2} joules.

Explanation:

We can represent this process by the First Law of Thermodynamics, in which gas does work on its surroundings and absorbs heat from there to describe its change in energy. In other words:

Q_{in} - W_{out} = \Delta E

Where:

Q_{in} - Heat absorbed by the gas, measured in joules.

W_{out} - Work done by the gas, measured in joules.

\Delta E - Change in energy, measured in joules.

If we know that Q_{in} = 1.36\times 10^{2}\,J and W_{out} = 3.19\times 10^{2}\,J, the change in energy of the gas is:

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\Delta E = -1.83\times 10^{2}\,J

The change in energy of the gas during the process is -1.83\times 10^{2} joules.

3 0
3 years ago
Just after a motorcycle rides off the end of a ramp and launches into the air, its engine is turning counterclockwise at 8325 re
alexgriva [62]

Answer:

\frac{Ie}{lm} = 1.10*10^{-3}

Explanation:

GIVEN DATA:

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ratio of moment of inertia of engine to motorcycle is given as

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\frac{Ie}{lm} = \frac{-(-4.2)}{(12125 - (8325))}

\frac{Ie}{lm} = 1.10*10^{-3}

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A "gauge 8" jumper cable has a diameter d of 0.326 centimeters. The cable carries a current I of 30.0 amperes. The electric fiel
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0.0979 N/c

Explanation:

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Substituting this into the first equation then E=P\times \frac {I}{\pi r^{2}}

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