1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
DanielleElmas [232]
2 years ago
9

A 50.0 Watt stereo emits sound waves isotropically at a wavelength of 0.700 meters. This stereo is stationary, but a person in a

car is moving away from this stereo at a speed of 40.0 m/s. The frequency of sound waves that the car receives is ________. In addition, when the car is 70.0 meters away from the speaker, the car will hear sound waves with a sound intensity level of _________ .
Physics
1 answer:
photoshop1234 [79]2 years ago
3 0

Answer:

a) f' = 432 Hz

b) I = 8.12*10^-4 W/m^2

Explanation:

a) To calculate the frequency of sound waves that car receives, you take into account the Doppler effect. In this case (observer moves away of the source) you have the following formula:

f'=f(\frac{v-v_o}{v+v_s})    (1)

where

f: frequency of the source = ?

v: speed of sound = 343 m/s

vo: speed of the observer = 40.0 m/s

vs: speed of the source = 0 m/s (stationary)

You replace the values of all parameters in the equation (1):

To calculate f' you first calculate the frequency of the sound wave, by using the following formula:

v=\lambda f\\\\

v: speed of sound

λ: wavelength = 0.700 m

f=\frac{v}{\lambda}=\frac{343m/s}{0.700m}=480Hz

Next, you replace the values of all parameters in the equation (1):

f'=(490Hz)(\frac{343m/s-40.0m/s}{343m/s})=432Hz

hence, the frequency perceived by the car is 432 Hz

b) To calculate the power of the sound wave, when the car is 70.0 maway from the speaker, you use the following formula:

I=\frac{P}{4\pi r^2}

P: power of the source = 50.0 W

r: distance to the source = 70.0 m

I=\frac{50.0 W}{4\pi(70.0m)^2}=8.12*10^{-4}\frac{W}{m^2}

hence, the intensity is 8.12*10^⁻4 W/m^2

You might be interested in
The weight of air in a column 1-m2 in cross section that extends from sea level to the top of the atmosphere is?
Sauron [17]

From sea level to the top of the atmosphere, a column of air with a 1-m2 cross section weighs 101,000 N.

To find the answer we have to know about the pressure.

<h3>What is Pressure?</h3>
  • The pressure at a point on a surface is the thrust acting per unit area around that point.

                    Pressure, P=\frac{Thrust}{Area}=\frac{F}{A}

  • A particular mass of air is contained in a column that rises from the ocean to the top of the atmosphere. Then,

                   P=P_a=1.013*10^5 pascal

Pa is the atmospheric pressure at the sea level.

  • By combining both the equations, we get the weight of air,

                                       \frac{F}{A}=P_a

              F=W=P_a*A=1.013*10^5*1=101300N

Thus, we can conclude that, the weight of air in a column 1-m2 in cross section that extends from sea level to the top of the atmosphere is 101300N.

Learn more about the pressure here:

brainly.com/question/24818722

#SPJ4

3 0
1 year ago
A marble block has dimensions of 0.4m x 0.4m x 2m. Knowing that the density of marble is 2,400 kg / m3, calculate the mass of th
Ostrovityanka [42]
So to find the mass we must use the formula D=M/V but because we don’t have the mass, we must use the formula M=DxV

So to find volume, just multiple the length (0.4m) width (0.4m) and height (2m) and you will get 0.32m as the volume. Now multiple this volume with your given density of 2,400 kg/m and you will get 768 kg as the mass of the marble block.

Final answer: 768 kilograms (kg) as mass of the marble block.
4 0
3 years ago
A nonconducting sphere has radius R = 2.81 cm and uniformly distributed charge q = +2.35 fC. Take the electric potential at the
Sladkaya [172]

Answer:

(a). The electric potential at 1.650 cm is -1.219\times10^{-4}\ V.

(b). The electric potential at 2.81 cm is -3.759\times10^{-4}\ V.

Explanation:

Given that,

Radius of sphere R=2.81 cm

Charge = +2.35 fC

Potential at center of sphere

V = 0

(a). We need to calculate the potential at a distance r = 1.60 cm

Using formula of potential difference

V_(r)-V_(0)=-\int_{0}^{r}{E(r)}dr

V_{r}-0=-\int_{0}^{r}{\dfrac{qr}{4\pi\epsilon_{0}R^3}}dr

V_{r}=-(\dfrac{qr^2}{8\pi\epsilon_{0}R^3})_{0}^{1.60\times10^{-2}}

V_{r}=-(\dfrac{2.35\times10^{-15}\times(1.60\times10^{-2})^2}{8\times\pi\times8.85\times10^{-12}\times(2.81\times10^{-2})^3})

V_{r}=-0.00012190\ V

V_{r}=-1.219\times10^{-4}\ V

The electric potential at 1.650 cm is -1.219\times10^{-4}\ V.

(b). We need to calculate the potential at a distance r = R

Using formula of  potential difference

V_{R}=-\dfrac{2.35\times10^{-15}}{8\pi\times8.85\times10^{-12}\times2.81\times10^{-2}}

V_{R}=-0.0003759\ V

V_{R}=-3.759\times10^{-4}\ V

The electric potential at 2.81 cm is -3.759\times10^{-4}\ V.

Hence, This is the required solution.

5 0
3 years ago
!!!!!<br> Is blood an incompressible fluid or a compressible fluid?
stiks02 [169]
Blood is an incompressible fluid. Hope this helps!
3 0
3 years ago
Read 2 more answers
I need to fill the gaps
andriy [413]

Answer:

1. combustion

2. oxygen

3. CO²

5 0
3 years ago
Other questions:
  • Which of the following has mechanical energy? Car battery Compressed spring Glowing incandescent lightbulb Nucleus of uranium at
    11·2 answers
  • An undamped 2.89-kg horizontal spring oscillator has a spring constant of 24.3 n/m. while oscillating, it is found to have a spe
    14·1 answer
  • An object with a mass of 78 kg is lifted through a height of 6 meters how much work is done
    8·1 answer
  • As a general rule, how does mass affect the force of friction?
    7·1 answer
  • 23. Challenge: A gas is heated so that it expands from a volume of 1.0L to a volume of 1.5 l. If the
    13·1 answer
  • What are three things that travel in waves
    14·2 answers
  • Two asteroids collide and stick together. The first asteroid has mass of 1.50 × 104 kg andis initially moving at 0.77 × 103 m/s.
    5·1 answer
  • ASAP!! Please help me out here ​
    14·1 answer
  • What are the two main processes carried out by the excretory system?​
    6·1 answer
  • A 0.300 kg mass is attached to
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!