posted by caleb .
A physics student sits by the open window on a train moving at 25 m/sec towards the east. Her boyfriend is standing on the station platform, sadly watching her leave. When the train is 150 meters form the station, it emits a whistle at a frequency of 3000 Hz.
What is the frequency of does the boyfriend hear ?
A chemistry student (with nothing better to do than ride around on trains all day) is on a west bound train moving at a velocity of 25 m/sec towards the station. Before the two trains pass each other, what frequency will he hear from the train whistle from the physics student's train?
What frequency will the chemistry student hear after his train passes the physics student's train?