Final answer:
The acceleration of the ball just before it strikes the ground is approximately 11.59 m/s^2.
Step-by-step explanation:
To calculate the acceleration of the ball just before it strikes the ground, we can use the formula:
acceleration = (final velocity - initial velocity) / time
In this case, the final velocity is 4 m/s, the initial velocity is 0 m/s (since the ball starts from rest), and the time of fall is not given. However, we can use the equation for free fall:
distance = (1/2) * acceleration * time^2
Since the ball falls 0.75m, we can substitute the values to solve for time:
(1/2) * acceleration * time^2 = 0.75m
Applying the quadratic formula, we find that the time of fall is approximately 0.345s. Plugging this value into the first equation gives us:
acceleration = (4m/s - 0m/s) / 0.345s ≈ 11.59 m/s^2.