Answer:
The rate at which the horizontal velocity of the ball changes every second is, 19%.
Step-by-step explanation:
The exponential decay function is given by:

Here,
<em>y </em>=<em> </em>final value
<em>a</em> = initial value
<em>r</em> = decay rate
<em>t</em> = time
The relationship between the elapsed time, <em>t</em>, in seconds, since Mustafa threw the ball, and its horizontal velocity, <em>V</em> (t) is:

The expression for the horizontal velocity of the ball represents the exponential decay function.
On comparing the two equations we get:

Thus, the rate at which the horizontal velocity of the ball changes every second is, 19%.