To find:
The situation in which the kinematic equation under free fall is applicable.
Step-by-step explanation:
The free fall is defined as the motion of an object under the influence of gravity.
The motion of the ball along the snooker board involves the applied force and the frictional force.
The motion of a bus along the road involves the applied force and the frictional force.
The motion of an airplane along the runway involves applied and frictional forces.
The raindrop moves towards the earth under the influence of gravity. Thus for this motion, the kinematic equations under the free fall are applicable.
Final answer:
The correct answer is option D.