Emphasis Preaching Journal
What is the sound barrier...
Illustration
What is the sound barrier? It is something one cannot see, but it matters tremendously in flying an airplane. It involves the air or atmosphere the aircraft meets when it is travelling 760 miles per hour, i.e., 13 miles per minute. At this speed the air seems to hold the plane back, but the newer models can push through the barrier and go smoothly along at a higher speed.
