Answer:
t=4.19 seconds
Step-by-step explanation:
Distance varies directly with the square of the time of the fall
It means,
D=kt^2
18ft in 2 seconds
D=kt^2
18=k*2^2
18=4k
k=18/4
=9/2
k=9/2
D=kt^2
D=79feet
79=9/2t^2
t^2=79÷9/2
t^2=79×2/9
=158/9
t=√158/√9
t=12.57/3
t=4.19 seconds
