Final answer:
Acceleration is the rate at which velocity changes. The magnitude of the acceleration can be determined by calculating the rate of change of velocity over time.
Step-by-step explanation:
Acceleration is the rate at which velocity changes. It is a vector quantity that has both magnitude and direction. The magnitude of the acceleration of a particle can be determined by calculating the rate of change of its velocity over time.
Therefore, the correct answer to the question is A) Velocity.
Acceleration is not equal to velocity, speed, force, or mass. Velocity refers to the rate of change of displacement, speed refers to the rate of change of distance traveled, force refers to the interaction between objects, and mass refers to the quantity of matter.