The change in speed each second on the way up is -9.8 m/s (or approximately -10 m/s).

Here's why:

* Gravity: The primary force acting on the ball is gravity, which pulls it downwards.

* Acceleration: Gravity causes a constant downward acceleration of approximately 9.8 m/s². This means the ball's downward velocity increases by 9.8 m/s every second.

* Upward Motion: Since the ball is traveling upwards, the change in speed is negative, indicating a decrease in upward velocity.

Therefore, the ball's upward speed decreases by 9.8 m/s every second.