A change in the body's velocity.
Here's why:
* Acceleration is the rate of change of velocity. This means it's not just about how fast something is moving (speed), but also about how that speed is changing over time.
* Velocity is a vector quantity: It has both magnitude (speed) and direction. Therefore, acceleration can be a change in speed, a change in direction, or both.
Examples:
* A car speeding up: The car's velocity is increasing, so it's accelerating.
* A car slowing down: The car's velocity is decreasing, so it's also accelerating (in this case, decelerating).
* A car turning a corner at constant speed: The car's direction is changing, so it's accelerating even though its speed remains the same.
Let me know if you have any other questions!
