Answer:
North of west
Explanation:
Given
Plane wishes to fly in west
but wind with speed 33.9 km/h towards south obstructing its path
so plane must fly at an angle of \theta w.r.t west such that it final velocity is towards west
Plane absolute speed=195 km/h
To fly towards west velocity in Y direction should be zero
thus 

so Plane should head towards
North of west in order to fly in west.
So plane
actual velocity is

C.an equal and opposite reaction

Strength: able to detect planets in a wide range of orbits, as long as orbits aren't face on
Limitations: yield only planet's mass and orbital properties