This might be a topic for physics, but I put it here.
I know that when a plane approaches the speed of sound...it's a pretty bumpy ride, but when you break the sound barrier, things smooth out. So I have a few questions:
1. What causes the increased turbulence when you approach mach 1?
2. Why does that turbulence smooth out after you break mach 1?
3. How has the shape of the plane reduced these effects?
Please explain in "high school" level physics.
Extra credit: Please explain to me why a propeller aircraft can't break the sound barrier.