1. The problem statement, all variables and given/known data So lets say a source is moving towards an observer at a speed of .9c where c is the speed of sound. the original frequency is 1 Hz. final frequency = (v(sound) / ((v(sound)-v(source))) * initial frequency so the final frequency would increase by a factor of 10. Now lets say that the observer was moving towards the source. final frequency = (v(sound) + v(observer))/ (v(sound)))intial frequency where in this case the final freuqnecy would only increase by a factor of 1.9Hz. Why am I getting different answers? Why does it matter whether the source is moving towards the observer or the observer towards the source?