Posted by Angelina on .
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?

Physics 12 
drwls,
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)