When you are standstill holding a flag, the flag flutters in the direction of wind. When you start running the direction of fluttering of the flag changes to the direction of the wind relative to you. In all case a flag flutters in the direction of the wind relative to the flag.
Holding a flag, when you run at 8 m/s due cast, the flag flutters in the north and when you run at 2m/s due south, the flag flutters in the northeast. If the wind velocity is unifoem and remain constant, find the wind velocity.