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
Temka [501]
3 years ago
14

Two trains are traveling on the same track and in the same direction. The first train, which is behind the second train, blows a

horn whose frequency is 269 Hz. The second train detects a frequency of 290 Hz. If the speed of the second train is 13.7 m/s, what is the speed of the first train?
Physics
1 answer:
Andrews [41]3 years ago
5 0

Answer:

37.545 m/s

Explanation:

f' = Actual frequency of horn = 269 Hz

f = Observed frequency of horn = 290 Hz

v = Speed of sound in air = 343 m/s

v_0 = Speed of second train = 13.7 m/s

v_s = Speed of first train

From Doppler effect we have

f=f'\dfrac{v-v_0}{v-v_s}\\\Rightarrow v_s=v-\dfrac{f'}{f}(v-v_0)\\\Rightarrow v_s=343-\dfrac{269}{290}(343-13.7)\\\Rightarrow v_s=37.545\ m/s

The speed of the first train is 37.545 m/s

You might be interested in
Why do slippery fluids such as oil reduce sliding friction
Gwar [14]
   fluid friction<span> occurs when an object moves through a liquid or gas. the force needed to overcome </span>fluid friction <span>is usually less then that needed to overcome </span>sliding friction<span>. the </span>fluid<span> keeps the surface from making direct contact and thus </span>reducing friction<span>.</span>
6 0
2 years ago
A retail gasoline pump is able to fill a 14.0 gallon automobile tank in 1.50 minutes. What is the mass flow rate deliverd by the
Ludmilka [50]

We have volume of gasoline = 14.0 gallon

Time taken to fill automobile tank = 1.50 minutes

So volume rate = 14.0 gallon/1.50 minutes = 9.33 gallon/ minute

We have density of gasoline = 0.77 kg/L = 6.073 lb/US gal

Mass rate = Density * Volume rate

                 = 9.33 gallon/ minute*6.073 lb/US gal = 56.68 lb/min

So mass flow rate delivered by the gasoline pump in lbm/min = 56.68

6 0
3 years ago
Read 2 more answers
Physics questions please help me
Ahat [919]
Hi,Find  answers from Task 5

1.(X+4)+(X)+(X+4)+(X)=50cm

4x+8=50cm

4x=42

X=10.5cm

Length=10.5+4=14.5cm

Width=10.5cm

Area= length × width=(10.5/100) × (14.5/100) =0.0152m2

2. Volume of a sphere= 4/3 ×π×r³

4/3 ×π×r³=3.2×10^-6 m³

r³=3.2×10^-6 m³/1.33×π

r³=7.64134761e-7

r=0.00914m

Surface area of the blood drop= 4πr²

=4×3.142×0.00914×0.00914=0.00105m²

3.

Equation of an ideal gas     = PV =n RT  

Equation for pressure, = P= n RT/V

Equation for the volume of an ideal gas= V= n RT/P

If the volume of gas doubles ,V(new)=  2n RT/P

Equation for temperature of an ideal gas, T = PV/n R

If temperature of gas triples, T (new)= 3PV/n R

New Equation for Pressure, = n× R× (3PV/n R)/(2n RT/P)

Pressure factor increase= P(new)/P(old)  ={ n× R× (3PV/n R)/(2n RT/P)}/{ n RT/V}

=3PV²/2n RT
5 0
2 years ago
Oxygen is needed by all cells of most organisms for the release of
pashok25 [27]

Answer:

From the SUN

Explanation:

Hope it helps!!!

Follow me if you want :)

7 0
1 year ago
Why does Mars not have an electric field and why
tangare [24]

Answer:

The difference lies in the planets' respective magnetic fields, because while Earth's magnetism comes from within, Mars' does not. Earth's magnetism comes from its core, where molten, electrically conducting iron flows beneath the crust. Its magnetic field is global, meaning it surrounds the entire planet

Explanation:

thanks for question

7 0
2 years ago
Other questions:
  • It is believed that during the late Cretaceous period sea levels rose drastically resulting in about a third of the Earth's pres
    9·2 answers
  • Can anyone give me the description of the element mercury is positioned on the periodic table of elements and a list of other el
    15·1 answer
  • An airplane with a speed of 92.3 m/s is climbing upward at an angle of 51.1 ° with respect to the horizontal. When the plane's a
    7·1 answer
  • Which of the following describes a protective put?
    7·1 answer
  • Synonym of an applied force
    10·1 answer
  • How do I find the atomic mass of an element?
    9·2 answers
  • Given two vectors A⃗ = 4.20 i^+ 7.00 j^ and B⃗ = 5.70 i^− 2.60 j^ , find the scalar product of the two vectors A⃗ and B⃗ .
    5·1 answer
  • In a potentiometer circuit a 1m long potentiometer PQ of resistance 10ohms is connected in series with a cell of e.m.f 9v with i
    7·1 answer
  • Use the information below for the next five questions:
    11·1 answer
  • Engineers are investigating the properties of a material for use as a wrapping product. Three identical
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!