In: Physics
The pilot of an airplane is trying to fly due west toward an airport. The airspeed of this plane is 900 km/hr. If the wind is blowing from the southwest at 100 km/hr, in what direction must his heading be? Find the speed of the plane relative to the ground.
v_wind = 100 km/hr (-cos45 i - sin45 j)
= - 70.7 i - 70.7 j km/h
v = v_wind + v_plane
v = (- 70.7i - 70.7j) + (900 cos(theta)i + 900 sin(theta)j)
v = (900 cos(theta) - 70.7)i + (900 sin(theta) - 70.7)j
v is along west.
so component along j will be zero.
900 sin(theta) - 70.7 = 0
sin(theta) = 4.5 deg North to west .....Ans
Speed of plane relative to ground
v = - 900 cos4.5 - 70.7
v = 968 km/ h ...........Ans