Answer:
Yes, it is possible for acceleration and velocity vectors to have opposite directions at a certain instant. This situation occurs when an object is slowing down or decelerating while still moving in a particular direction.
To illustrate this, consider a car traveling in the positive direction along a straight road. If the car starts to apply the brakes, it will experience a deceleration or negative acceleration. At that instant, the velocity vector (which represents the direction and magnitude of the car's motion) will still be in the positive direction, while the acceleration vector (which represents the change in velocity) will be in the negative direction, opposite to the velocity vector. The car's speed will decrease, and eventually, the velocity vector will align with the acceleration vector as the car comes to a stop.
So, while velocity and acceleration vectors typically have the same direction (e.g., both positive or both negative), there are instances when they can have opposite directions.