9514 1404 393
Answer:
15 seconds
Step-by-step explanation:
Put the given heights in the equation and solve for t.
h(t) = -16t² +3600
0 = -16t² +3600 . . . . h(t) = 0 at ground level
16t² = 3600 . . . . . . . add 16t²
t² = 3600/16 = (60/4)² = 15² . . . . . divide by 16
t = 15 . . . . . . . . . . . . take the square root
It will take 15 seconds for the phone to hit the ground.
