An alert physics student stands beside the tracks as a train rolls slowly past. He notes that the frequency of the train whistle is 465Hz when the train is approaching him and 441Hz when the train is receding from him. Using these frequencies, he calculates the speed of the train. What value does he find?

Please show step by step. I know the answer but CANNOT figure out how to calculate it.

Question

An alert physics student stands beside the tracks as a train rolls slowly past. He notes that the frequency of the train whistle is 465Hz when the train is approaching him and 441Hz when the train is receding from him. Using these frequencies, he calculates the speed of the train. What value does he find?

Please show step by step. I know the answer but CANNOT figure out how to calculate it.

anonymous · Answer

vary good question i have been just waiting forever for this question to show up so i can learn

surry99 · Answer

Hint: Look up Doppler effect

anonymous · Answer

Use the doppler formulae that give you the apparent frequency of the sound -
the form is slightly different for the case of an approaching or receding source.
You can then take the ratio of these two equations, knowing the observed frequencies, and you will end up with an equation that can be solved for the speed of the source. You will also have to assume a value for the speed of sound in air.

anonymous · Answer

When I work the problem using the Doppler Equation I get an extremely small number as opposed to the answer of 9.09m/s^2

surry99 · Answer

show us the equation you are using and your substitution