In introductory kinematics, what quantity is defined as the rate at which velocity changes with time?

• A. Acceleration
• B. Momentum
• C. Displacement
• D. Speed

Answer: (A)

Verified step by step guidance

1. Understand that the problem is asking for a quantity that measures how velocity changes over time.
2. Recall that velocity is a vector quantity that describes both the speed and direction of an object.
3. Recognize that the rate of change of velocity with respect to time is defined as acceleration.
4. Acceleration can be mathematically expressed as \(\vec{a} = \frac{d\vec{v}}{dt}\), where \(\vec{v}\) is velocity and \(t\) is time.
5. Therefore, the quantity defined as the rate at which velocity changes with time is acceleration.