Final answer:
As the tennis ball rises to its highest point, its velocity decreases while its acceleration remains constant due to the force of gravity.
Step-by-step explanation:
As the tennis ball rises to its highest point, its velocity will decrease while its acceleration remains constant.
This is because the tennis ball is experiencing free fall motion, where the only force acting on it is gravity. Gravity causes the ball to accelerate downwards at a constant rate of 9.8 m/s^2. As the ball rises, it is moving against the direction of this acceleration, which results in a decrease in velocity.
However, it's important to note that the acceleration will remain constant because gravity continues to act on the ball, even as it rises. The net force acting on the ball is always directed downwards.