Final answer:
The ball hits the ground after approximately 0.5 seconds.
Step-by-step explanation:
To solve this problem, we can use the vertical motion model, which is represented by the equation h = -16t^2 + vt + s. In this case, the initial height (s) is 4 feet and the velocity (v) is 30 feet per second.
Setting h = 0, we can solve for t to find when the ball hits the ground:
0 = -16t^2 + 30t + 4
Using the quadratic formula, t = (-b ± √(b^2 - 4ac)) / 2a, where a = -16, b = 30, and c = 4:
t = (-30 ± √(30^2 - 4(-16)(4))) / (2(-16))
t = (-30 ± √(900 + 256)) / -32
t = (-30 ± √1156) / -32
t = (-30 ± 34) / -32 --> t = 1/2 or t = -17/16
Since time cannot be negative, the ball hits the ground after approximately 0.5 seconds.