As a tornado moves, its speed increases. The functions S(d) = 93logd+65 relates the speed of the wind, S, in miles per hour, near the center of a tornado to the distance that the tornado has traveled,d, in miles.

Question

a) Graph this function.
b) Calculate the average rate of change for the speed of the wind at the center of a tornado from mile 10 to mile 100.
c) Estimate the rate at which the speed of the wind at the center of a tornado is changing at the moment it has traveled its 10th mile and its 100th mile.
d) Use your graph to the discuss how the rate at which the speed of the wind at the center of a tornado changes as the distance that the tornado travels increases.

Answer 1

http://www.wolframalpha.com/input/?i=93log(d)%2B65+for+d%3E0

Note that it's just the usual log graph, shifted up and scaled.