Answer
869 feet
Work Step by Step
We are given in Example 5 that the height of an object at t seconds can be found by the equation $P(t)=-16t^{2}+1125$. To find the height at $t=4$ seconds, we must find the value of $P(4)$.
$P(4)=-16(4^{2})+1125=-16\times16+1125=-256+1125=869$ feet
