Answer:
![3 m/s^2](https://img.qammunity.org/2020/formulas/physics/high-school/e277r1yt0qgac2ozy5wgsv7jw75xpmuilc.png)
Step-by-step explanation:
I assume you are asking for the acceleration of the ball, not the velocity (in fact, the velocity is already given).
The acceleration is:
![a=(v-u)/(t)](https://img.qammunity.org/2020/formulas/physics/middle-school/rbz9i28f98a6dvpx0ghax9pxq7qjfdf5sd.png)
where in this case we have:
v = 24 m/s is the final velocity
u = 0 is the initial velocity
t = 8 s is the time interval for the velocity to change
Solving the equation,
![a=(24-0)/(8)=3 m/s^2](https://img.qammunity.org/2020/formulas/physics/middle-school/nct1kgwb3fvcz2e9nb9k5k7iv4enfqo0zk.png)