Question

1. A penny is dropped from the top of the empire state building. The function h(t) = -16t^2 +1250 describes the height of the penny, h, after t seconds. How many seconds does it take for
the penny to hit the ground?
Round your answer to the nearest tenth of a second.

Answer 1

Answer: $8.83\ s$

Step-by-step explanation:

Given

Height of the dropped penny is given by

$h(t)=-16t^2+1250$

When penny hit the ground, $h(t)=0$

$\therefore -16t^2+1250=0\\\Rightarrow 16t^2=1250\\\\\Rightarrow t^2=\dfrac{1250}{16}\\\\\Rightarrow t=\sqrt{\dfrac{1250}{16}}\\\\\Rightarrow t=8.83\ s$

Thus, it takes 8.83 s to hit the ground.