Final answer:
Centrifugal force and the horizontal lift component in an airplane's coordinated turn act in the same direction because the horizontal lift provides the centripetal acceleration necessary for the turn. Therefore, the current answer is d) Centrifugal force and horizontal lift component act in the same direction.
Step-by-step explanation:
The relationship between centrifugal force and the horizontal lift component in a coordinated turn is such that they act in the same direction.
During a turn, an airplane banks to create a horizontal component of lift that accelerates the airplane towards the center of the turn, which in the frame of the airplane is perceived as a centrifugal force moving outward.
However, because centrifugal force is a fictitious force observed in the rotating (non-inertial) frame of reference of the airplane, the real force acting towards the center of the turn, the centripetal force, is provided by the horizontal component of the lift.
Thus, the correct answer is (d) Centrifugal force and horizontal lift component act in the same direction.