Given data:
* The mass of the baseball is 0.31 kg.
* The length of the string is 0.51 m.
* The maximum tension in the string is 7.5 N.
Solution:
The centripetal force acting on the ball at the top of the loop is,
![\begin{gathered} T+mg=(mv^2)/(L)_{} \\ v^2=(L(T+mg))/(m) \\ v=\sqrt[]{(L(T+mg))/(m)} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/dmkyuevj9btx35kxhkgx72d4c6fgbv7q4u.png)
For the maximum velocity of the ball at the top of the vertical circular motion,
![v_(\max )=\sqrt[]{(L(T_(\max )+mg))/(m)}](https://img.qammunity.org/2023/formulas/physics/college/14sfldzyymqcdkspmtgt6mhrrmkghshtjt.png)
where g is the acceleration due to gravity,
Substituting the known values,
![\begin{gathered} v_(\max )=\sqrt[]{\frac{0.51(7.5_{}+0.31*9.8)}{0.31}} \\ v_(\max )=\sqrt[]{(0.51(10.538))/(0.31)} \\ v_(\max )=\sqrt[]{17.34} \\ v_(\max )=4.16\text{ m/s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/y395sdmkmm0uv8w06cdcigbybnlqe75h6c.png)
Thus, the maximum speed of the ball at the top of the vertical circular motion is 4.16 meters per second.