## College Physics (4th Edition)

The minimum wind velocity is $50~m/s$ east
To find the minimum wind velocity, we should assume that the plane's airspeed and the wind velocity are both directed to the east. Note that if the plane's airspeed was in another direction, a larger wind velocity would be required. Let $v_{pg}$ be the plane's ground speed. Let $v_{pa}$ be the plane's airspeed. Let $v_{ag}$ be the wind velocity. We can find the minimum wind velocity: $v_{pg} = v_{pa}+v_{ag}$ $v_{ag} = v_{pg} - v_{pa}$ $v_{ag} = 210~m/s-160~m/s$ $v_{ag} = 50~m/s$ The minimum wind velocity is $50~m/s$ east