1. A train moving at 25 m/s is traveling towards Mr. Anderson, who is standing in the middle of the tracks. What frequency does Anderson hear if the train has a horn frequency of 1000 Hz?

Does the distance travelled by an oscillating mass between times t=0 and t2 equal the displacement of the particle over the same time period if t2> t/2? hint: consider a sine wave starting at t1=0, then consider a closing wave starting at t1=0, for your explanation.