If a baseball has a negative velocity and a negative acceleration, its speed is decreasing.
Velocity is a vector quantity that includes both magnitude (speed) and direction. In this case, the negative velocity indicates that the baseball is moving in the opposite direction of a chosen positive reference direction. Acceleration, on the other hand, represents the rate of change of velocity and also includes both magnitude and direction.
When the velocity and acceleration have the same sign (both negative in this case), it means that the baseball is slowing down. This is because the acceleration is acting in the opposite direction to the velocity, which results in a decrease in speed. Therefore, the speed of the baseball is decreasing.