[tex]\bf \textit{initial velocity}\\
h = -16t^2+v_ot+h_o \qquad \text{in feet}\\
\\ \quad \\
v_o=\textit{initial velocity of the object}\\
h_o=\textit{initial height of the object}\\
h=\textit{height of the object at "t" seconds}\\\\
-----------------------------\\\\
H(t)= -16t^2+4+18t\implies
\begin{array}{llll}
H(t)= -16t^2+18t&+4\\
&\uparrow \\
&h_o
\end{array} [/tex]