0 a large increase in the force opposing a moving object as its speed reaches the speed at which sound travels: --
Can you imagine taking old ladies and little children through the sound barrier?
It is like the sound barrier to an aeroplane.
With the aircraft of today it is impossible to eliminate altogether the possibility of a pilot breaking the sound barrier inadvertently.
The delay was primarily because the specialised materials to form the sound barrier had not been obtained at that time.
It was a perfect summer day, and there was no cloud to form anything like a sound barrier.
This reminds me of the difficulties which confronted the aircraft manufacturers when aircraft were being buffeted against the sound barrier.
In all these cases, they can break the sound barrier.
We have just about one aircraft which will break the sound barrier.
