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jasenka [17]
3 years ago
13

If a sound with frequency fs is produced by a source traveling along a line with speed vs. If an observer is traveling with spee

d vo along the same line from the opposite direction toward the source, then the frequency of the sound heard by the observer is fo = c + vo c − vs fs where c is the speed of sound, about 332 m/s. (This is the Doppler effect.) Suppose that, at a particular moment, you are in a train traveling at 45 m/s and accelerating at 1.1 m/s2. A train is approaching you from the opposite direction on the other track at 46 m/s, accelerating at 1.6 m/s2, and sounds its whistle, which has a frequency of 459 Hz. At that instant, what is the perceived frequency that you hear? (Round your answer to one decimal place.) Hz How fast is it changing? (Round your answer to two decimal places.) Hz/s
Physics
1 answer:
Alexus [3.1K]3 years ago
7 0

Answer:

457.81 Hz

Explanation:

From the question, it is stated that it is a question under Doppler effect.

As a result, we use this form

fo = (c + vo) / (c - vs) × fs

fo = observed frequency by observer =?

c = speed of sound = 332 m/s

vo = velocity of observer relative to source = 45 m/s

vs = velocity of source relative to observer = - 46 m/s ( it is taking a negative sign because the velocity of the source is in opposite direction to the observer).

fs = frequency of sound wave by source = 459 Hz

By substituting the the values to the equation, we have

fo = (332 + 45) / (332 - (-46)) × 459

fo = (377/ 332 + 46) × 459

fo = (377/ 378) × 459

fo = 0.9974 × 459

fo = 457.81 Hz

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3 years ago
A wire carries 3.7 A of current. A second wire is placed parallel to the first 8.0 cm away. What is the current flowing through
IgorC [24]

Answer:

The current in second wire is 5.0 A.

(B) is correct option.

Explanation:

Given that,

Current in first wire = 3.7 A

Distance = 8.0 cm

We need to calculate the magnetic field due to the current carrying wire

Using formula of magnetic field

B=\dfrac{\mu_{0}I}{2\pi r}

Where, I = current

r = distance

Put the value into the formula

For first wire

B = \dfrac{\mu_{0}\times3.7}{2\pi \times3.4\times10^{-2}}...(I)

For second wire,

The distance is 8-3.7 =  4.3 cm

B' = \dfrac{\mu_{0}\times I'}{2\pi \times(8-3.4)\times10^{-2}}...(II)

The magnetic field in both the wires,

From equation (I) and (II)

\dfrac{\mu_{0}\times3.7}{2\pi \times3.4\times10^{-2}}= \dfrac{\mu_{0}\times I'}{2\pi \times(8-3.4)\times10^{-2}}

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8 0
3 years ago
A hockey player swings her hockey stick and strikes a puck. According to Newtons 3rd law of motion which of the following is a r
Korvikt [17]

<u>Complete Question:</u>

A hockey player swings her hockey stick and strikes a puck. According to Newton’s third law of motion, which of the following is a reaction to the stick pushing on the puck?

A. the puck pushing on the stick .

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C. the player pushing on the stick .

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<u>Correct Option:</u>

According to Newton’s third law of motion the puck pushing on the stick is a reaction to the stick pushing on the puck.

<u>Option: A</u>

<u>Explanation:</u>

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a student drops an object from the top of a building which is 19.6 m high. How long does it take the object to fall to the groun
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Here's a formula that's simple and useful, and if you're really in
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This one is so simple and useful that I'd suggest memorizing it,
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This formula tells how far an object travels in how much time,
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Divide each side by 4.9 :       4  =           T²

Square root each side:           2  =          T

When an object is dropped in Earth gravity,
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