Question

Pls explain the answer

Answer 1

nothing to it, the next or each fall happens when its height is 0, namely if you from a 2nd floor drop a pencil to the 1st floor, the height of the pencil is whatever distance between both floors, and as it falls, that height begins to decrease for the pencil, well, because is falling and approaching the ground, when it reaches the ground, that height equation or h(t) = 0.

`h(t)=-16t^2+1450\implies \stackrel{h(t)}{0}=-16t^2+1450\implies 16t^2=1450 \\\\\\ t^2=\cfrac{1450}{16}\implies t^2=\cfrac{725}{8}\implies t=\sqrt{\cfrac{725}{8}}\implies t\approx 9.52~seconds`