How is acceleration defined?

• A. As the speed of an object
• B. As the rate of change of velocity
• C. As the distance covered per unit time
• D. As the amount of force applied

Answer: (B)

Acceleration is defined as the rate of change of velocity of an object over time. This concept encompasses how quickly an object's speed or direction is changing, indicating not only increases in speed but also decreases (deceleration) or changes in direction while maintaining constant speed. This definition is fundamental in physics, as it links directly to Newton's second law of motion, which states that acceleration is produced when a force acts on a mass. The greater the force applied, the greater the acceleration, provided the mass remains constant.

Understanding acceleration as a rate of change of velocity also highlights its vector nature, meaning it has both magnitude and direction. For example, a car that speeds up on a straight road is experiencing acceleration, while a car making a turn at constant speed is also accelerating due to the change in direction of its velocity.

In contrast to the other choices, speed alone does not convey direction, making it an incomplete description of how motion changes. Distance covered per unit time refers to speed rather than acceleration. The amount of force applied relates to the cause of acceleration but does not define it. Therefore, defining acceleration as the rate of change of velocity provides a comprehensive understanding of an object's changing motion.