One form of the formula that meteorologists use to calculate wind chill temperature (WC) is
WC = 35.74 + 0.6215t - 35.75s0.16 + 0.4275t s0.16
where s is the wind speed in mph and t is the actual air temperature in degrees Fahrenheit. Suppose temperature is constant at 15∘.
(a) Express wind chill WC as a function of wind speed s.
(b) Find the rate of change of wind chill with respect to wind speed when the wind speed is 25 mph.
(c) Interpret your answer to part (b).