Final answer:
The subject of this question is Physics, as it involves analyzing the motion of a car. The question provides information about the direction and speed of the car, which can be analyzed using principles of Physics.
Step-by-step explanation:
The subject of this question is Physics. The question describes the motion of a Ford Mustang driven by a woman in her 20's, providing information about the direction and speed of the car. Physics studies the motion of objects and can help analyze the speed and direction of the car in this scenario.