An Efficiency Study Showed That the Total Number of Cell $N(t)=-0.5 t^{3}+3 t^{2}+7 t, \quad 0 \leq t \leq 4$

Short Answer

An efficiency study showed that the total number of cell phones assembled by the average worker at a manufacturing company t hours after starting work at 8
a.m. is given by
$N(t)=-0.5 t^{3}+3 t^{2}+7 t, \quad 0 \leq t \leq 4$
Sketch the graph of the function N, and interpret your result.