posted by Angelina .
I need help on solving this problem
A plane with an air speed of 400km/hr wants to go north but a wind of 70 km/hr is blowing west. What must be the planes heading (to go north)? What will be its resulting ground speed?
The plane must have an air speed component of 70 km/hr east to compensate for the 70 km/h wind speed west. That will leave a north component of air speed of sqrt[400^2 - 70^2] = 393.8 km/h
Required heading = arcsin 70/400 = 10.1 degrees (E of N)