Question 1162343
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<pre>

You should find the time "t" from the equation


    h(t) = 0,   which in your case is  -16t^2 + 16,   or


    16t^2 = 16.


Cancel the factor 16 in both sides and get  


      t^2 = 1,

which implies

     t = {{{sqrt(1)}}} = 1 second.


It is your answer.
</pre>

Solved, explained and completed.