To determine the acceleration of the ball, we can use the kinematic equation that relates the displacement, initial velocity, time, and acceleration:
Displacement = Initial velocity × Time + 0.5 × Acceleration × Time^2
At the highest point, the displacement is zero because the ball stops momentarily before falling back down. Therefore, we have:
0 = 15 m/s × 2 s + 0.5 × Acceleration × (2 s)^2
0 = 30 m + 2 s^2 × Acceleration
Since we're solving for the acceleration, we can rearrange the equation:
2 s^2 × Acceleration = -30 m
Acceleration = -30 m / (2 s^2)
Acceleration = -15 m/s^2
The negative sign indicates that the acceleration is in the opposite direction of the initial velocity. In this case, the negative acceleration represents the deceleration due to gravity, which causes the ball to slow down as it reaches its highest point before falling back down.
Therefore, the acceleration of the ball is -15 m/s^2.