A train coming toward you at 15 m/s blasts a signal which you hear as 400 Hz. What frequency will you hear after the train passes? Assume the speed of sound is 343 m/s.

Question

A train coming toward you at 15 m/s blasts a signal which you hear as 400 Hz.  What frequency will you hear after the train passes?  Assume the speed of sound is 343 m/s.

bobpursley · Answer

Laura,I am not going to do your thinking for you. I will be happy to critique it.

drwls · Answer

Read your lesson about the Doppler effect and apply the appropriate formula.

Cjay · Answer

I guess a better addition to the question would be which form of the equation would one use? Also, in the case of the source velocity, would it be (-) implying a velocity away from the observer or would it be (+) as a default? I have the same question on a practice exam.