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Alik [6]
3 years ago
12

If 20 beats are produced within a single second, which of the following frequencies could possibly be held by two sound waves tr

aveling through a medium along a common path at the same time
A. 38 Hz and 63 Hz
B. 18 Hz and 26 Hz
C. 47 Hz and 55 Hz
D. 22 Hz and 42 Hz
Physics
2 answers:
solong [7]3 years ago
6 0
If 20 beats are produced within one second the frequencies that could possibly be held by two sound waves traveling through a medium along a common pants at the same time are <span>b. 22  and 42 </span>
zhuklara [117]3 years ago
4 0

The correct choice is

D. 22 Hz and 42 Hz.

In fact, the beat frequency is given by the difference between the frequencies of the two waves:

f_B = |f_1 -f_2|

In this problem, the beat frequency is f_B=20 Hz, therefore the only pair of frequencies that gives a difference equal to 20 Hz is

D. 22 Hz and 42 Hz.

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Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are maintained at a temperature of 13
svet-max [94.6K]

Answer:

5945.27 W per meter of tube length.

Explanation:

Let's assume that:

  • Steady operations exist;
  • The heat transfer coefficient (h) is uniform over the entire fin surfaces;
  • Thermal conductivity (k) is constant;
  • Heat transfer by radiation is negligible.

First, let's calculate the heat transfer (Q) that occurs when there's no fin in the tubes. The heat will be transferred by convection, so let's use Newton's law of cooling:

Q = A*h*(Tb - T∞)

A is the area of the section of the tube,

A = π*D*L, where D is the diameter (5 cm = 0.05 m), and L is the length. The question wants the heat by length, thus, L= 1m.

A = π*0.05*1 = 0.1571 m²

Q = 0.1571*40*(130 - 25)

Q = 659.73 W

Now, when the fin is added, the heat will be transferred by the fin by convection, and between the fin and the tube by convection, thus:

Qfin = nf*Afin*h*(Tb - T∞)

Afin = 2π*(r2² - r1²) + 2π*r2*t

r2 is the outer radius of the fin (3 cm = 0.03 m), r1 is the radius difference of the fin and the tube ( 0.03 - 0.025 = 0.005 m), and t is the thickness ( 0.001 m).

Afin = 0.006 m²

Qfin = 0.97*0.006*40*(130 - 25)

Qfin = 24.44 W

The heat transferred at the space between the fin and the tube will be:

Qspace = Aspace*h*(Tb - T∞)

Aspace = π*D*S, where D is the tube diameter and S is the space between then,

Aspace = π*0.05*0.003 = 0.0005

Qspace = 0.0005*40*(130 - 25) = 1.98 W

The total heat is the sum of them multiplied by the total number of fins,

Qtotal = 250*(24.44 + 1.98) = 6605 W

So, the increase in heat is 6605 - 659.73 = 5945.27 W per meter of tube length.

5 0
3 years ago
On average, how many stars would we have to search before we would expect to hear a signal? assume there are 500 billion stars i
Keith_Richards [23]

We would have to search at least 5,000,000,000 (5 billion) stars before we would expect to hear a signal.

To find out the number of stars that we will need to search to find a signal, we need to use the following formula:

  • total of stars/civilizations
  • 500,000,000,000 (500 billion) stars / 100 civilization = 5,000,000,000 (5 billion)

This shows it is expected to find a civilization every 5 billion stars, and therefore it is necessary to search at least 5 billion stars before hearing a signal from any civilization.

Note: This question is incomplete; here is the complete question.

On average, how many stars would we have to search before we would expect to hear a signal? Assume there are 500 billion stars in the galaxy.

Assuming 100 civilizations existed.

Learn more about stars in: brainly.com/question/2166533

7 0
2 years ago
A photon with an energy E = 2.12 GeV creates a proton-antiproton pair in which the proton has a kinetic energy of 96.0 MeV. What
Oksanka [162]

Answer:

The kinetic energy of the anti proton is 147.4 MeV.

Explanation:

Given that,

Energy = 2.12 GeV

Kinetic energy = 96.0 MeV

We need to calculate the kinetic energy of the anti proton

Using formula of energy

E_{photon}=m_{p}c^2+m_{np}c^2+K.E_{p}+K.E_{np}

We know that,

m_{p}c^2=m_{np}c^2

So, E_{photon}=2mc^2+K.E_{p}+K.E_{np}

K.E_{np}=E_{photon}-(2mc^2+K.E_{p})

Put the value into the formula

K.E_{np}=2.12\times10^{9}-2\times938.3\times10^{6}-96\times10^{6}

K.E_{np}=147.4\ MeV

Hence, The kinetic energy of the anti proton is 147.4 MeV.

6 0
3 years ago
How far would a jet going 155 m/s travel in 9 s?
docker41 [41]

Answer:

1,395 m

Explanation:

155×9

multiply m/s by 9s

5 0
3 years ago
You add 50 mL of water at 20C to 200 mL of water at 70C. What is the most likely final temperature of the mixture?
Veseljchak [2.6K]
100*20 + 200*80 = 300* T
T = 60
5 0
3 years ago
Read 2 more answers
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