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BaLLatris [955]
2 years ago
7

a whistle you use to call your hunting dog has a frequency of 21 khz, but your dog is ignoring it. you suspect the whistle may n

ot be working, but you can't hear sounds above 20 khz. to test it, you ask a friend to blow the whistle, then you hop on your bicycle.At what minimum speed should you ride to know if the whistle is working?
Physics
1 answer:
laila [671]2 years ago
4 0

To solve this problem we will apply the concepts related to the Doppler effect. According to this concept, it is understood as the increase or decrease of the frequency of a sound wave when the source that produces it and the person who captures it move away from each other or approach each other. Mathematically this can be described as

f = f_0 (\frac{v-v_0}{v})

Here,

f_0 = Original frequency

v_0 = Velocity of the observer

v = Velocity of the speed

Our values are,

v = 340m/s \rightarrow \text{Speed of sound}

f = 20kHz \rightarrow \text{Apparent frequency}

f_0 = 21kHz \rightarrow \text{Original frequency}

Using the previous equation,

f = f_0 (\frac{v-v_0}{v})

Rearrange to find the velocity of the observer

v_0 =v (1-\frac{f}{f_0})

Replacing we have that

v_0= (340m/s)(1-\frac{20kHz}{21kHz})

v_0 = 16.19m/s

Therefore the velocity of the observer is 16.2m/s

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D. Evaporation

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3 years ago
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Singly charged gas ions are accelerated from rest through a voltage of 10.3 V. At what temperature (in K) will the average kinet
Natasha_Volkova [10]

Answer:

Temperature of the gas molecules is 7.96 x 10⁴ K

Explanation:

Given :

Ions accelerated through voltage, V = 10.3 volts

The work done to change the position of singly charged gas ions is given by the relation :

W = q x V

Here q is charge of the ions and its value is 1.6 x 10⁻¹⁹ C.

Average kinetic energy of gas molecules is given by the relation:

K.E. = \frac{3}{2}kT

Here T is temperature and k is Boltzmann constant and its value is 1.38 x 10⁻²³ J/K.

According to the problem, the average kinetic energy of gas is equal to the work done to move the singly charged ions, i.e. ,

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\frac{3}{2}kT = qV

Rearrange the above equation in terms of T :

T= \frac{2qV}{3k}

Substitute the suitable values in the above equation.

T=\frac{2\times1.6\times10^{-19}\times10.3 }{3\times1.38\times10^{-23} }

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5 0
3 years ago
A 1.5-kg ball is throw at 10 m/s. What is the balls momentum?
alexdok [17]

Answer : The momentum of ball is, 15 kg.m/s

Explanation :

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Harrizon [31]
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water vapor in the atmosphere would build up and build up and build up,
until the atmosphere could not hold any more water vapor. 

-- The water would stay there in the atmosphere.  There would never be
any more rain, sleet, hail, fog, drizzle, mist, or snow.

-- Rivers flow out of lakes and ponds, carrying lake water to the sea. 
Rain keeps the lakes refilled. 
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-- At the instant when the atmosphere became full of all the water vapor
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. . . . . When you washed the dishes, you could leave them standing in the
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. . . . . You could hang up your bath towel and the laundry in your room or
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. . . . . When you boiled a pot of water on the stove, I'm not sure exactly
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. . . . . It would be pretty bad for people and animals.  We generate a lot of heat
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Our dogs don't even perspire.  The only way they can get rid of heat is to
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