Answer:
- At point P and in toward the tencer of the track (D.)
Explanation:
As it is correctly recalled at the end of the question, acceleration is the rate of change of velocity.
Velocity is a vector: it has magnitude (called speed) and direction.
Since the car drives at constant speed, the accelereration (the change in the velocity) is not the result of the change of speed but of the change of direction.
In points R and Q the motion of the car is rectilinear; thus, you conclude that there is not acceleration at those points (neither the speed nor the direction change).
On the point P the car changes its direction appreciably, thus it is at point P that the longest acceleration occurs.
Regarding the direction at which the acceleration vector points toward, it is so that the car changes from going vertical upward to going (a littile) toward the right, to follow the clockwise path along the track: the acceleration has to be in toward the center of the track, because in that way the car is pulled and forced to follow the track.
