According to Newton’s second law, what aspect of a system is directly proportional to the force applied to it?

Newton's second law states that the force acting on an object is equal to the mass of that object multiplied by its acceleration (F = ma). From this relationship, it becomes clear that acceleration is the aspect of a system that is directly proportional to the force applied to it.

As the force increases, so does the acceleration, assuming the mass of the object remains constant. This is fundamental in understanding how forces influence the movement of objects; for example, applying a greater force to a vehicle will result in a greater acceleration, making it speed up more rapidly.

Acceleration is a measure of how quickly the velocity of an object changes. Therefore, while velocity and distance are related to motion, they are influenced by factors such as time and initial conditions rather than being directly proportional to the force applied. In contrast, mass is a constant property of the object itself and does not change with applied forces. Thus, acceleration is the correct answer that aligns with the principles set forth in Newton’s second law of motion.