As an aircraft increases speed (TAS) the airflow over some part of the fuselage or wings may be accelerated up to the speed of sound and a shock wave will form. These shock waves cause more drag, less lift, turbulent flow, and a reduction in effectiveness or even a reversal of control reactions.
Airplanes produce lift from the air moving over their wings. Stall speed is a metric that refers to the minimum speed required for an airplane to produce lift. When airplanes fly slower than their respective stall speed, they won't produce lift. ... If an airplane's speed drops below its stall speed, it won't produce lift.
Running for 300 m at 3 m/s takes 100 seconds and running at 300 m at 6 m/s takes 50 seconds. 100 s + 50 s = 150 s (total time). Total distance is 600 m, so 600 m/ 150 s = 4 m/s.
