Answer:
1.7 seconds
Step-by-step explanation:
we have
[tex]H=-16t^2+vt+s[/tex]
where
v is the initial velocity (in feet per second)
s represents the initial height (in feet)
In this problem we have
[tex]v=0[/tex] ---> because the object is dropped
[tex]s=45\ ft[/tex]
substitute
[tex]H=-16t^2+45[/tex]
Remember that
When the chestnut hit the ground the value of H is equal to zero
so
For H=0
[tex]-16t^2+45=0[/tex]
solve for t
[tex]16t^2=45\\t^2=2.8125\\t=\pm1.7\ sec[/tex]
therefore
The solution is t=1.7 sec
