Final answer:
To solve for the time 't' when the height is 126 feet using the equation h = -16t², divide 126 by -16, then take the square root of the result. The positive root is approximately 2.81 seconds, which is the time when the height will be 126 feet.
Step-by-step explanation:
To find the time 't' when the height 'h' is 126 feet using the equation h = -16t², we can plug in the value for 'h' and solve for 't' as follows:
126 = -16t²
First, we'll divide both sides of the equation by -16 to get:
-7.875 = t²
Next, we take the square root of both sides. Keep in mind that we'll have two solutions, one positive and one negative, but since time cannot be negative, we only consider the positive root:
t = √7.875
After calculating we get:
t ≈ 2.81 seconds
Thus, the time when the height is 126 feet is approximately 2.81 seconds.