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Bad White [126]
3 years ago
8

A high speed train is traveling at a speed of 44.7 m/s when the engineer sounds the 415 Hz warning horn. The speed of sound is 3

43 m/s. What is the wavelength of the sound, as perceived by the person standing at a crossing when the train is a) approaching and b) find the frequency when leaving the crossing?
Physics
1 answer:
il63 [147K]3 years ago
8 0

Answer:

Explanation:

Speed of the source of sound = v = 44.7 m/s

Speed of sound = V = 343 m/s

a) Apparent  frequency as the train approaches = f =  [V /(V -v) ] × f

= [343 / (343 - 44.7) ] × 415  = 477.18 Hz

Wave length =  λ = v / f = 343 / 477.18 = 0.719 m

b) Frequency heard as the train leaves = f ' =  [V / ( V + v) ] f

                                                                     = [343 / { 343 + 44.7 ) ] x 415

                                                                      = 367.2 Hz

Wavelength when leaving = v / f = 343 / 367.2 = 0.934 m

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3 years ago
An object travels with a constant speed in a circular path. The net force on the object is
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In this problem, we have an object travelling at constant speed in a circular path. The fact that the trajectory of the object is circular means that the direction of motion of the object is constantly changing: this means that its velocity is changing, so it has an acceleration. And therefore, a net force is acting on it. The force that keeps the object travelling in the circular path is called centripetal force, and it is directed towards the center of the circle (because it prevents the object from continuing its motion straight away).

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8 0
3 years ago
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Answer:

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ValentinkaMS [17]

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