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
allsm [11]
2 years ago
12

A train is traveling away from you at 120 km/h. it blows its whistle, and you hear a tone of 0.400 kHz. Take the speed of sound

to be 340 m/s. What frequency does the whistle actually produce? A) 444 Hz. B) 439 Hz C) 364 Hz D) 361 Hz
Physics
1 answer:
Vaselesa [24]2 years ago
5 0

Answer:B)439.21 Hz

Explanation:

Given

velocity of train v=120 km/h\approx 120\times \frac{5}{18}=33.33 m/s

frequency of train f_a=0.400 kHz\approx 400 Hz

speed of sound c=340 m/s

frequency from Doppler effect can be calculated by

f_a=(\frac{c}{c+v})\cdot f

400=(\frac{340}{340+33.33})\cdot f

400=\frac{340}{373.33}\cdot f

f=400\times 1.098

f=439.21 Hz

You might be interested in
(LC)Light fixtures and placement that create shadows on the set, that obscure or completely hide action in certain areas of the
Sedaia [141]

The correct answer is true.

It is true that light fixtures and placement that create shadows on the set, that obscure or completely hide action in certain areas of the set, or that change as the main character’s emotional state changes are all ways that lighting can be used to heighten the drama and suspense in dramatic films.

Lighting plays an important role in film making because it can create scenes that enhance the de drama of the moment or the right mood that the director wants to share. Lighting in the film is an art because the basic principle is that the scene needs to look natural. From that principle, filmmakers and light specialist cand create many kinds of dramatic or jubilation moments if they know how to apply light principles to each scene.

5 0
3 years ago
The atmospheric pressure on the top of the Engineering Sciences Building (ESB) is 97.6 kPa, while that in Room G39-ESB (ground f
Stells [14]

Answer:

Δ h = 52.78 m

Explanation:

given,

Atmospheric pressure at the top of building = 97.6 kPa

Atmospheric pressure at the bottom of building = 98.2 kPa

Density of air = 1.16 kg/m³

acceleration due to gravity, g = 9.8 m/s²

height of the building = ?

We know,

Δ P = ρ g Δ h

(98.2-97.6) x 10³ = 1.16 x 9.8 x Δ h

11.368 Δ h = 600

Δ h = 52.78 m

Hence, the height of the building is equal to 52.78 m.

6 0
3 years ago
A student's life was saved in an automobile accident because an airbag expanded in front of his head. If the car had not been eq
dexar [7]

Answer:    

Compared to windshield the airbag exerts much lesser force  

Explanation:

Impulse is defined as change in momentum of the object when it is acted upon by a force during interval of time

<em>Impulse = Impulsive force *time</em>

I = F*Δt

If the object should be bought to rest from certain velocity there should be change in momentum. If the duration in which the momentum is increased then there would be less force applied and hence less damage.

Airbags are used to reduce the force experience by the people when they are met with accident by extending the time required to stop the momentum.

During the collision, the passenger is carried towards the<em> windshield</em> and if they are stopped by collision with wind shield the force will be larger and more damage.But if they are hit with airbag then the force will be less due to increased time.

The change is momentum will be the same with or without momentum but its the time that decides the impact of force.By making it longer the force become less.

<em>Thus compared to the windshield the airbag exerts much lesser force.</em>

<em>   </em>

8 0
3 years ago
Which changes in energy form are illustrated in the diagram.
Grace [21]
It would be B since it starts with the solar energy which is converted to electricity with the solar panels, which then creates mechanical energy for the fans blades to move and sound for the radio.

Hope that helps :)
6 0
2 years ago
Can a person run at a speed of 20 meters per second
tensa zangetsu [6.8K]

Answer:

No

Explanation:

The fastest recorded time for a person to run 100 metres is 9.58 seconds, which is the equivalent of 10.4 metres per second

6 0
1 year ago
Read 2 more answers
Other questions:
  • Please help me with this homework
    10·2 answers
  • ________ is the average kinetic energy of each atom.<br><br> radiation<br> temperature<br> potential
    10·1 answer
  • A 37 N block rests on a horizontal surface. The coefficients of static and kinetic friction between the surface and the block ar
    11·1 answer
  • Hydrogen gas was cooled from 150c to 50c. its new volume is 75.0 ml. what was its original volume
    5·1 answer
  • An object is moving with a constant velocity of 278 m/s. How long will it take it to travel 7500 m, using the formula Delta X=Vt
    11·1 answer
  • Diffusion of water through a differentially permeable membrane is called
    6·2 answers
  • Explain in detail what happens to the Earths surface after an earthquake due to the force of tension
    8·1 answer
  • A 33 kg cart rests at the top of a hill. If the cart has a PE of 4800J, what is the height of the hill?
    14·2 answers
  • A force of 10 N making an angle 30 with horizontal .its horizontal component wll be​
    10·1 answer
  • Mental health can be improved by (5 points)
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!