Cadet Competition Written Practice Exam

What is the rate of change in velocity with respect to time known as?

1. Speed

2. Momentum

3. Acceleration

4. Force

The correct answer is: Acceleration

The rate of change in velocity with respect to time is defined as acceleration. Acceleration measures how quickly an object's velocity increases or decreases over a given time period. It can be both positive, indicating an increase in speed, or negative, known as deceleration, indicating a decrease in speed. Understanding acceleration is fundamental in physics and engineering because it describes not just motion, but how motion changes. For example, when a car speeds up as it moves from a stop, it experiences positive acceleration. Similarly, a car coming to a stop experiences negative acceleration. This concept is crucial for analyzing motion in various contexts, such as in vehicle dynamics or projectile motion. In contrast, speed refers to how fast an object is moving without regard to its direction, so it does not account for changes in velocity. Momentum relates to the quantity of motion an object has and combines mass and velocity. Force is an interaction that causes an object to accelerate but is not the same as the acceleration itself. Therefore, acceleration is specifically the term that aligns with the definition provided in the question.