Answer:
About 0.559 seconds
Step-by-step explanation:
The height equation is:
[tex]h=-16t^2+h_0[/tex]
Where [tex]h_0[/tex] is the initial height of the book, which is 5, so we can write:
[tex]h=-16t^2+5[/tex]
Now, we want time it took for the book to reach ground (h = 0)
So, we substitute h = 0 and solve for t:
[tex]h=-16t^2+5\\0=-16t^2+5\\16t^2=5\\t^2=0.3125\\t=0.5590\\t=0.559[/tex]
It took about 0.559 seconds for the book to reach the ground