When a car turns and slows down but keeps going straight, its velocity changes in two ways: direction and magnitude.
Change in direction: Turning the car means it deviates from its original straight path. The velocity vector, which represents both the magnitude (speed) and direction of motion, will experience a change in direction to match the new path the car is following. For example, if the car was initially moving in a north direction and turns towards the east, its velocity vector will rotate accordingly.
Change in magnitude: Slowing down means the car's speed decreases. The magnitude of the velocity vector decreases as the car decelerates. However, even if the speed reduces, the car can still maintain a non-zero velocity as long as it continues moving in a straight line.
In summary, when a car turns and slows down but keeps going straight, its velocity changes both in direction and magnitude. The direction of the velocity vector adjusts to match the new path, while the magnitude decreases as the car slows down.