Answer:
at about t = 1.62
Step-by-step explanation:
42 feet below a height of 45 feet is a height of 45-42 = 3 feet. You want to find t such that
h(t) = 3
-16t^2 +45 = 3
-16t^2 = -42 . . . . subtract 42
t^2 = -42/-16 = 21/8 . . . . . divide by -16
t = √2.625 ≈ 1.620 . . . . . take the square root
The trampolinist will land on the trampoline about 1.62 seconds after stepping off the platform.
