5.
A cowboy puts his right ear to a railway track and hears the
sound of an approaching train. He then hears the sound of the
same train with his left ear through the air 0.87 s later.
If the speed of sound in the air is 340 m/s and the speed
through steel is 6100 m/s, should the cowboy be getting out of
the way (how far away is the train)?
