An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approaches and then passes by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?

Answers

Answer 1

Answer:

The frequency heard by the observer will be "7351.35 Hz".

Explanation:

The given values are:

Source,

[tex]V_s=30 \ m/s[/tex]

Frequency of source,

[tex]F_s=8000 \ Hz[/tex]

Speed of sound,

[tex]C=340 \ m/s[/tex]

As we know,

⇒  [tex]F=(\frac{C+V_r}{C+V_s} )F_s[/tex]

Here,

[tex]V_r=0[/tex]

So that the formula will be:

⇒  [tex]F=(\frac{C}{C+V_s} )F_s[/tex]

        [tex]=\frac{340}{340+30}\times 8000[/tex]

        [tex]=7351.35 \ Hz[/tex]


Related Questions

_SF4 + _H2O -> _H2SO3 + _HE

Answers

Answer:

SF4 + 3H2O → H2SO3 + 4HF

Explanation:

I found it

8. Isotopes of the same element have different
numbers of neutrons.
numbers of protons.
numbers of electrons.
atomic numbers.
C.
d.

Answers

Im pretty sure that its c

A ball at rest rolls across a frictionless floor at 12.0 m/s/s. How far will it travel in
8.00 s?

Answers

Answer:

The distance, d travelled by the ball is 768 metres.

Explanation:

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of final speed from the initial speed all over time.

Hence, if we subtract the final speed from the initial speed and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;

[tex]Acceleration (a) = \frac{initial \; speed - final \; speed}{time}[/tex]

[tex]a = \frac{v - u}{t}[/tex]

Where,

a is acceleration measured in [tex]ms^{-2}[/tex]

v and u is initial and final speed respectively, measured in [tex]ms^{-1}[/tex]

t is time measured in seconds.

Given the following data;

Acceleration = 12.0m/s²

Time, t = 8secs

Velocity =?

First, we would calculate its velocity;

[tex]a = \frac{v - u}{t}[/tex]

Since the ball rolls at rest, initial velocity is zero (0).

[tex]V = a * t[/tex]

[tex]V = 12 * 8[/tex]

[tex]Velocity = 96ms^{-1}[/tex]

We can now solve for the distance;

[tex] Velocity = \frac{distance}{time}[/tex]

Therefore,

[tex]Distance = velocity * time[/tex]

[tex]Distance = 96 * 8[/tex]

Distance = 768m.

A man walks 30 ft. East, then 25 ft. South. How far is the man away from where
he started?
39.05 ft
32 ft
16.6ft
10ft

Answers

C. 16.6 is the answer.

what is an example of a non credible online source?
A a chat room for music lovers
B a website run by a university
C the white house's website
D a site for a volunteer organization.
help im being timed 01:37:17​

Answers

A. a chat room for music lovers
The correct answer is a

A stone is projected vertically upwards with a velocity of 30m/s from a tower of height 50m negleting air resistance,determine the maximun height it reached from the ground (g=10ms^-1)​

Answers

It takes 3 seconds for the stone to reach the brightest point ( velocity becomes zero )
Vertical displacement = 1/2 * 10 * 3^2 = 45m
Maximum height from ground = 50 + 45 = 95m

Convert 2.5 mm to micrometers

Answers

Answer:

2500

Explanation:

Answer:

2500

Explanation: 1 mm is 1000 micrometers pls give me brainlist

If an automobile travels at 30 m/sec for 2 minutes, the car have traveled ?

Answers

The car has traveled 3,600 m.
30 x 60 = 1,800 (converts m/sec into m/hour)
1,800 x 2 = 3,600

Answer:

1800 times 2= 3600

Explanation:


Please help me

1. Rank the following items from MOST
inertia to LEAST inertia: Chick Fil A
Biscuit, Feather, Elephant, a 1st grader.

Answers

Answer:firt answer corrcect who answerd

Explanation:

Feather, Biscuit, a 1st grader, Elephant is order of  LEAST inertia to MOST inertia.

What is inertia?

Inertia is the resistance of an object to any change in motion. Inertia is proportional the mass of the object: in fact, as we experience in common situations, the larger the mass of an object, the more difficult it is to change its motion.

Inertia of an object is its inherited property. It is the measure of its mass. It is clear that the inertia of an object depends directly on its mass. Mass of an object is the amount of matter contained in it. It is same at every location.

Given that in the case four thing Biscuit, Feather, Elephant, a 1st grader out of which Feather, Biscuit, a 1st grader, Elephant is order of  LEAST inertia to MOST inertia.

Feather, Biscuit, a 1st grader, Elephant is order of  LEAST inertia to MOST inertia.

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What is the wave speed of a 1,000 Hz wave with a wavelength of 0.04 m?

Answers

Wave speed = 40 m/s

Explanation:

Wave speed = frequency x wavelength

Wave speed = 1000 * 0.04

Wave speed = 40 m/s

Which one is correct for question 5?

Answers

Answer:

the object has a constant net force greater than zero acting on it.

Explanation:

Think about multiplying the mass of each student by a factor to calculate each student’s kinetic energy. Is there a common factor that works for every student? If so, what’s this factor?

Answers

Answer:

KE= (1/2)mv^2

given m, the remaining components of the equation are=

1/2v^2?

Explanation:

KE= (1/2)mv^2

plug in...

=(1/2)(27 kg)(3 m/s)^2= 121.5

KE= 121.5 J

Answer:

Multiplying the mass of any student by a factor of 4.5 gives the kinetic energy of the student.

HURRRY PLEASEEEEE!!!

In photosynthesis, what two compounds are produced during the light-dependent reaction then used in the light-independent reaction?

A) ATP and NADPH
B) ATP and ADP
C) NADP+ and ADP
D) NADPH and NADP+

Answers

Answer:

The answer choice is: A) ATP and NADPH

Explanation:

Your question is asking the components that are created during light - dependent reaction, and then used in independent reaction. That would be shown in the photo below!

ATP and NADPH is created from light dependent then transfered and transformed into different components from the calvin cycle (light independent cycle)

Two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH

Photosynthesis is a process that takes place in the Chloroplast of plant cells. Autotrophs obtain their energy source (food) in the presence of sunlight.

The photosynthesis process occurs in two distinct stages; light-dependent reaction and light-independent reactions.

the light reactions take place in the thylakoid membranes of chloroplasts.The light-dependent reactions use light energy to make two molecules needed for the next stage of photosynthesisThese molecules are the energy storage molecule ATP and the reduced electron carrier NADPH.

Thus, two compounds are produced during the light-dependent reaction then used in the light-independent reaction - A) ATP and NADPH

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A runner is jogging in a straight line at a

steady vr= 8.4 km/hr. When the runner is

L= 6.3 km from the finish line, a bird begins

flying straight from the runner to the finish

line at vb= 42 km/hr (5 times as fast as the

runner). When the bird reaches the finish

line, it turns around and flies directly back to

the runner.

Answers

Answer:

Total distance traveled by bird is 10.5 km.

Explanation:

Given that,

Velocity of runner= 8.4 km/hr

Distance = 6.3 km

Velocity of bird = 42 km/hr

Suppose, How far does the bird travel?

We need to calculate the time of bird

Using formula of time

[tex]t=\dfrac{d}{v_{b}}[/tex]

Put the value into the formula

[tex]t=\dfrac{6.3}{42}[/tex]

[tex]t=0.15\ hr[/tex]

We need to calculate the distance runner travels during time period

Using formula of distance

[tex]d=v_{r}\times t[/tex]

[tex]d=8.4\times0.15[/tex]

[tex]d=1.26\ km[/tex]

We need to calculate the distance of runner to FL

Using distance

[tex]d'=6.3-1.26[/tex]

[tex]d'=5.04\ km[/tex]

We need to calculate the net closing speed between runner and bird

Using speed

[tex]v'=v_{r}+v_{b}[/tex]

[tex]v'=8.4+42[/tex]

[tex]v'=50.4\ km/hr[/tex]

We need to calculate the time for runner and bird to meet

Using formula of time

[tex]t=\dfrac{d}{v'}[/tex]

Put the value into the formula

[tex]t=\dfrac{5.04}{50.4}[/tex]

[tex]t=0.1\ hr[/tex]

We need to calculate the distance covered by runner

Using formula of distance

[tex]d=vt[/tex]

Put the value into the formula

[tex]d=8.4\times0.1[/tex]

[tex]d=0.84\ km[/tex]

We need to calculate the distance covered by bird to runner

Using formula of distance

[tex]d=vt[/tex]

Put the value into the formula

[tex]d=42\times0.1[/tex]

[tex]d=4.2\ km[/tex]

We need to calculate the total distance

Using distance

[tex]D=6.3+4.2[/tex]

[tex]D=10.5\ km[/tex]  

Hence, Total distance traveled by bird is 10.5 km.

Help help help help help

Answers

Please mark me brainliest

As we move through the visible spectrum, red to violet (right to left in the image), the wavelength __________ and the frequency ____________.

Answers

Decreases and increases

Violet tending toward ultraviolet or higher frequency

Red is lower frequency “infra-red”. Low frequency.

what is universe made off​

Answers

Answer:

I mean, correct me if I'm wrong for some reason, but I think its Matter?

Answer:

The Universe is thought to consist of three types of substance: normal matter, 'dark matter' and 'dark energy'. Normal matter consists of the atoms that make up stars, planets, human beings and every other visible object in the Universe.

Explanation:

help me to answer this please ​

Answers

Answer:

ok

Explanation:

21. Compare and contrast beta particles to the electrons that surround neutral atoms.
UGH HELP MEEE PLSS

Answers

Beta particles come from the nucleus. Electrons are found around the nucleus.
Beta particles normally travel very fast out of a nucleus in a straight line. Electrons normally orbit the nucleus of an atom.

They both have the same mass and the same charge.

An object is dropped from a 32 m tall building. How fast will it be going when it
strikes the ground?

Answers

Answer:

If there is no air resistance, it would be

25.04 m/sec    when it hits the ground

Please help!! i will mark brainly

Answers

Answer:

The object sped up, moved at constant speed, then slowed down.

Calculate the mmoi of a tire that weighs 15.0 kg and has a radius of 30.0 (treat it as a hoop )

Answers

Answer:

Kinetic Energy and Work: The mass moment of inertia of the wheel about ... The wheel is made from a 5-kg thin ring and two 2-kg slender ... determine the maximum angular velocity of the wheel if it is ... velocity of the pulley at the instant the 20-lb weight moves ... The spool has a mass of 40 kg and a radius of gyration of.

Explanation:

Help asap please. How would I do this?​

Answers

Answer:

what to answer I don't know sorry

mark as branliest

Which device manages the flow of current in an electric circuit?

the wire
the switch
the battery
the light bulb

Answers

Answer:

b

Explanation:

Switch is the device that manages the flow of current in an electric circuit.

What is meant by current ?

Current in a conductor is defined as the rate of flow of charge through the conductor per unit time.

Here,

An electric circuit consists of various components such as wire, switch, light bulb, battery, etc.

The wire is a piece of metal strand through which the current flows in an electrical circuit.

Switch is the device that controls the flow of current in an electric circuit by turning on and off mechanism.

Battery is the device that provides the necessary potential difference for the production of electrical energy in an electric circuit.

A light bulb is the device which is used to produce light from the electricity in an electric circuit.

Hence,

Switch is the device that manages the flow of current in an electric circuit.

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A man runs at 7.5 m s-1 due east across the deck of a ship which moves at 10.0 m s-1 due north. Determine the resultant velocity of the man( his velocity relative to the water)

Answers

Answer:

12.5 m/s North/east

Explanation:

I thought of it as a graph. I basically just found the distance between the points (0,0) and (10, 7.5)!

The resultant velocity of the man is 12.5 m/s.

What is velocity?

The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.

Velocity of the man: v₁ = 7.5 m/s (due east )

Velocity of the ship: v₂ = 10 m/s. ( due north.)

Hence, the man and the ship move in perpendicular direction.

So,  his velocity relative to the water = the resultant velocity of the man

= √(7.5² + 10²) m/s = 12.5 m/s.

Hence, resultant velocity of the man is 12.5 m/s.

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Which two options are forms of potential energy?
O A. Electrical energy
B. Elastic energy
O C. Magnetic energy
D. Light energy
O E. Sound energy

Answers

Answer(s): A and B :)

A. Electrical energy  B. Elastic energy  are the forms of potential energy.

What is potential energy?

Potential energy is the energy possess by an object because due to its position relative to other objects, stresses within itself, its electric charge, or other factors.

Types of Potential energy:

Elastic potential energy  - It is stored in objects that can either be stretched or compressed. The more the object is stretched or compressed, the more elastic potential energy it will  have. A classic example is a stretched rubber bandElectric potential energy - Is the energy that is needed to move a charge against an electric field. We need more energy to move a charge  in the electric field, but also more energy to move it through a stronger electric field.

Therefore,

Electrical energy , Elastic energy are the forms of potential energy.

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Enzymes have a certain temperature at which they work best. Temperatures above and
below this point will decrease enzyme activity. Which graph best illustrates the effect of
temperature on enzyme activity?

Answers

Answer:

B

Explanation:

It shows the increase in temperature and the decrease.

The best activity of enzyme is It increases and decreases.

What are Enzymes?

A biological catalyst called an enzyme is usually always a protein. It accelerates a certain chemical reaction in the cell.

The enzyme is continuously employed during the reaction and is not destroyed. Each enzyme molecule found in a cell is unique and tailored to a particular chemical reaction.

A biological catalyst called an enzyme is often a protein, though it can also be RNA. A catalyst's purpose is to quicken the rate at which a reaction takes place.

Therefore, The best activity of enzyme is It increases and decreases.

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What can a machine do?
O A. Decrease the work needed to do something
B. Make the work you do feel easier
C. Multiply the energy of a system
O D. Create energy in the form of work

Answers

Answer:

B. Make the work you do feel easier

Answer:

Something a machine can do is Decrease the work needed to do something and a machine can also do make the work you do easier.

Explanation:

How can you find the frequency or period of ocean waves?

Answers

Answer:    As you probably have seen in the ocean or a lake, the stronger the wind, the higher the waves. The period and wavelength can be expressed in terms of their reciprocals, the wave frequency ω = 2(pi)/T, and the wave number κ = 2(pi)/λ.

Explanation:     To find the period, we solve for T=1f, given the value of the frequency (f=2s−1). T=12 s−1=0. 5 s. Since one definition of wavelength is the distance a wave has traveled after one complete cycle (or one period), the values for the wavelength (λ=0.9m) as well as the frequency are given.

Giving brainliest!

1. Use Newton’s Laws to explain why an object in space that has no motion has to be shoved to move in the first place.


2. Use Newton’s Laws to explain why a bowling ball will slow down and stop when rolled on a flat surface, like a street.


3. Use Newton’s Laws to explain why, when a 100Kg astronaut throws a 9Kg bowling ball forward in space, she moves backward but slower.

Answers

Answer:

An object in space that has no motion has to be shoved to move in the first place because of newton's first law of motion.                            A bowling ball will slow down and stop when rolled on a flat surface, like a street because of rolling friction which comes under Newton's first law of motion.                                   When a 100Kg astronaut throws a 9Kg bowling ball forward in space, she moves backward but slower, this is because of Newton's third law of motion.      

Explanation:

This is due to Newton's first law of motion, explaining that an object in space that has no movement has to be moved to move in the first place. There is no external force or gravitational force in space, so the body can stay at rest and be forced to move first. Explaining why a bowling ball, like a street, can slow down and stop when rolled on a flat surface. This, again, is attributed to Newton's first law of motion. Due to rolling friction, it happens. The electrons on the surface of the ground in the atoms push against the electrons that touch the ground in the atoms on the surface of the ball as you roll a ball on the ground. A rolling ball stops when the surface on which it rolls opposes its motion. A ball rolling, due to friction, ceases.Explaining that when a 100 kg astronaut throws a 9 kg bowling ball forward in space, she travels backward but slower, due to Newton's third motion rule , which states that when force is applied, each body exhibits equal and opposite reaction. In this case, the astronaut's mass is greater, so the ball's acceleration will be less than the astronaut 's mass (since the body's mass is inversely proportional to the acceleration). Therefore, because of the reverse direction and slowly because of no gravitational force in space, the girl shifts backward while tossing the ball forward in space.

Newton's Law of Motion -  

FIRST  LAW -  The first law of Newton states that if a body is at rest or moving in a straight line at a constant speed, it will stay at rest or continue to travel at constant speed in a straight line unless it is acted upon by a force.

SECOND LAW -   The second law of Newton is a quantitative explanation of the changes that a force can cause in a body 's motion. It states that the rate of change of a body's momentum in time is proportional to the force exerted on it in both magnitude and direction.  

THIRD LAW -     The third law of Newton notes that they apply forces to each other when two bodies interact, which are equal in magnitude and opposite in direction. Often known as the law of action and reaction, the third law is. In analyzing static equilibrium problems, where all forces are balanced, this law is essential, but it also applies to bodies in uniform or accelerated motion.  

Hence , all the three explainations consist of newton's first and third  laws of motion.

                                                                         

                                             

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