Here's why:
* Constant Acceleration: The only force acting on the ball throughout its flight is gravity. This means the ball experiences a constant downward acceleration of 9.8 m/s².
* Velocity at the Top: At the very top of its trajectory, the ball momentarily has a velocity of 0 m/s. This is because it's changing direction from upward to downward motion.
* Acceleration vs. Velocity: It's important to note that acceleration and velocity are different. Even though the ball's velocity is zero at the top, its acceleration is still -9.8 m/s² due to gravity.
Think of it like this: Even when you're momentarily stopped at the top of a roller coaster hill, you still feel the force of gravity pulling you downward, causing you to accelerate toward the next drop.
