Final answer:
The question lacks necessary details to calculate the ball's acceleration. Additional information like time or angle of release is required to provide an accurate answer using appropriate physics equations.
Step-by-step explanation:
The question does not provide sufficient information to directly calculate the ball's acceleration with the data given (1.5 meter long string and a release velocity of 7.2 m/s). The question might be missing additional information, such as the time or angle of release, which is crucial for determining the acceleration in this case. Without this information, we cannot accurately provide an answer to the original question about the ball's acceleration. However, we can explore calculating acceleration in various contexts using relevant physics equations and concepts, such as using kinematic equations for a ball thrown vertically or analyzing circular motion for a pendulum.