The wave heights $h$ in the open sea depend on the speed $v$ of the wind and the length of time $t$ that the wind has been blowing at that speed. Values of the function $h=f(v, t)$ are recorded in feet in Table 4.
(a) What is the value of $f(40,15)$ ? What is its meaning?
(b) What is the meaning of the function $h=f(30, t)$ ? Describe the behavior of this function.
(c) What is the meaning of the function $h=f(v, 30)$ ? Describe the behavior of this function.