# A 500-Hz whistle is moved toward a listener at a speed of 10.0 m/s. At the same time, the listener moves at a speed of 20.0 m/s in a direction away from the whistle. What is the apparent frequency heard by the listener? (The speed of sound is 340 m/s.)

To determine the apparent frequency heard by the listener is equal to 545.45 Hz.

Given the following data:

• Observer velocity = 20.0 m/s
• Frequency of sound = 500 Hz
• Source velocity = 10.0 m/s
• Speed of sound = 340 m/s

To determine the apparent frequency heard by the listener, we would apply Doppler's effect of sound waves:

Mathematically, Doppler's effect of sound waves is given by the formula:

Where:

• V is the speed of a sound wave.
• F is the actual frequency of sound.
• is the observer velocity.
• is the source velocity.
• is the apparent frequency.

Substituting the given parameters into the formula, we have;

Apparent frequency = 545.45 Hz.

f'  = 485 Hz

Explanation:

given,

Frequency of whistle,f = 500 Hz

speed of source, v_s = 10 m/s

Speed of observer, v_o - 20 m/s

speed of sound,v = 340 m/s

Apparent frequency heard = ?

Using Doppler's effect formula to find apparent frequency

f'  = 485 Hz

Hence, the apparent frequency is equal to 485 Hz.

## Related Questions

What are five features that erosion forms along a river?

Deposition, ground water, and delta.

A football player at practice pushes a 60 kg blocking sled across the field at a constant speed. The coefficient of kinetic friction between the grass and the sled is 0.30. How much force must he apply to the sled?

The amount of force the football player must apply to the sled is 176.4 Newton.

Given the following data:

• Mass of sled = 60 kg
• Coefficient of kinetic friction = 0.30

We know that acceleration due to gravity (g) on Earth is equal to 9.8

To find how much force the football player must apply to the sled:

Mathematically, the force of kinetic friction is given by the formula;

Where;

• Fk represents the force of kinetic friction.
• μ represents the coefficient of friction.
• m represents the mass.
• g is the acceleration due to gravity.

Substituting the given parameters into the formula, we have;

Force, Fk = 176.4 Newton.

180N

Explanation:

Using Newton's law of motion;

∑F = m x a       --------------------(i)

Where;

∑F = Resultant force

m = mass of the object (sled in this case)

a = acceleration of the sled

Calculate the resultant force;

Since the direction of motion is horizontal, the horizontal forces acting on the sled are the;

i. Applied force () in one direction and;

ii. Frictional force () in the other direction to oppose motion

Therefore, the resultant force ∑F is the vector sum of the two forces. i.e;

∑F = -  -----------------------(i)

Frictional force is the product of the coefficient of kinetic friction (μ) and weight(W) of the sled. i.e

= μ x W

Where;

W = mass(m) x gravity(g)

W = m x g

=> = μmg

Substitute into equation (ii)

∑F = - μmg

Substitute ∑F into equation (i)

- μmg = ma  -------------------(iii)

Since the motion is at constant speed, it means acceleration is zero (0)

Substitute a = 0 into equation (iii) to give;

- μmg = 0

=> = μmg

Substitute the values of μ = 0.3, m = 60kg and g = 10m/s² into the above equation to give;

=>  = 0.3 x 60 x 10

=> = 180N

This means that the applied force should be 180N

What kind of friction occurs as a fish swims through water?

It must be sliding friction, because the fish is already in motion.

You throw a rock upward. The rock is moving upward, but it is slowing down. If we define the ground as the origin, the position of the rock is _____ and the velocity of the rock is _____. A. positive, positive
B. positive, negative
C. negative, positive
D. negative, negative

A. Positive, positive

Explanation:

As we defined the ground is the origin, as long as the rock is above the ground, its position would always be positive.

As for velocity, as long as the rock is moving upwards, its direction is also upward, so its velocity is always positive. The velocity will become negative when the rock falls down.

A. Positive, Positive

Explanation:

Light does not move infinitely fast but has a finite speed. We normally use ""c"" to indicate the speed of light in science. Write down the value for the speed of light in metric units: c = _________.

6.71 × 10^8 mi/hr

Explanation:

Light is usually defined as an electromagnetic wave that is comprised of a definite wavelength. It is of both types, visible and invisible. The light emitted from a source usually travels at a speed of about 3 × 10^8 meter/sec. This speed of light is commonly represented by the letter 'C'.

To write it in the metric system, it has to be converted into miles/hour.

We know that,

1 minute = 60 seconds

60 minutes = 1 hour

1 kilometer = 1000 meter

1 miles = 1.6 kilometer

Now,

=

= 1.08 × 10^12 m/ hr (meter/hour)

=

= 6.71 × 10^8 mi/hr (miles/hour)

Thus, the value for speed of light (C) in metric unit is 6.71 × 10^8 mi/hr.

The first attempt at publishing a list of relative atomic masses was made by

Dalton Was the first one to attempt a publishing list of relative atomic masses.

John Dalton Was the first one to attempt a publishing list of relative atomic masses.

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The ring of fire is located on the edge of what of what ocean

It is the Pacific Ocean.

There's not really a way to give evidence, so hope it helps!

A star that's actively fusing hydrogen into helium is aa. supergiant. b. main-sequence star.
c. red giant.
d. white dwarf.

C.) Red-Giant

It is the stage, which comes in life cycle of every star, when they perform Nuclear fusion inside their core.

Hope this helps!
C red giant -
actively fumes hydrogen to helium

Which objects play the roles of the sun earth and moon