(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A jet is flying horizontally from A to B. When the plane is directly overhead at B, a person on the ground (C) hears the sound coming from A. ABC is a right triangle in B. The angle BCA = 36 degrees.

The average temperature is 20 degrees Celsius. If the speed of the plane at A is 170 m/s, what is the speed at B, assuming that it has constant acceleration?

2. Relevant equations

f=1/T f: frequency; T: period

v= λ*f = λ/T λ: wavelength

f_{observer}= f_{plane}*((v+v_{o})/(v+v_{p})) v=343m/s

3. The attempt at a solution

First off I don't see what steps to take to come up with the answer. There must some implicit data to take into consideration but I can't figure it out.

What I assume, since there is a right triangle with an angle given, is that one distance has to be found (AC) to find AB with sin.

I found the acceleration by taking t=1second. I know that the sound travels at 343m/s on AC and the speed the plane has after one second on AB is found by calculating v_{plane}= sin(36)*343= 201.6m/s so the acceleration is a= (201.6-170)/1s= 31.6m/s^{2}

I can't figure out how to get the distance from A to C or A to B.

PS: those values are given from my homework given by the teacher, on the book the same problem has 164m/s for the speed of the plane at A, same angle. The answer for the speed at B is 239m/s

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# Homework Help: Sound waves and the doppler effect

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