Newton had discovered the isothermal velocity of sound in air.
牛顿发现了在空气中恒温声音的速度。
2
By the time he passed four thousand feet he had reached terminal velocity, the wind was a solid beating wall of sound against which he could move no faster.
If you go much faster, the center of lift moves back on the wing, pushing the nose down and increasing velocity, until you soon approach the speed of sound.