* Velocity describes both the speed and direction of an object. A negative velocity simply means the object is moving in the opposite direction of whatever we've defined as positive.

* Acceleration describes how the velocity is changing. A positive acceleration means the velocity is becoming more positive (increasing in the positive direction, or decreasing in the negative direction).

Here are some scenarios where this could happen:

* Object slowing down: Imagine a car traveling backward (negative velocity). If you hit the brakes, you're applying a force in the opposite direction of its motion, causing it to slow down. This force produces a positive acceleration, even though the car's velocity is still negative.

* Object changing direction: Think of a ball thrown upward. As it goes up, its velocity is positive, but gravity is pulling it downward, causing a negative acceleration. When the ball reaches the peak of its trajectory, its velocity momentarily becomes zero, and then it starts to fall back down. The acceleration is still negative, but now the velocity is also negative.

Key Point: Acceleration and velocity are independent quantities. Acceleration tells you how velocity is changing, not what the value of the velocity is.