Answer: The height of the object at any time t is given by the function s(t) = -16t² + 64. When the object reaches the ground, its height will be 0. So we need to solve the equation:
-16t² + 64 = 0
Dividing both sides by -16, we get:
t² - 4 = 0
Adding 4 to both sides, we get:
t² = 4
Taking the square root of both sides (and remembering to include both the positive and negative roots), we get:
t = ±2
Since time cannot be negative, the only valid solution is:
t = 2
Therefore, it will take the object 2 seconds to reach the ground.
Explanation: