The grade x of a hill is a measure of its steepness. For example, if a road rises 10 feet for every 100 feet of horizontal distance, then it has an uphill grade of x = 10/100 or 10%. See the figure. The braking distance D for a car traveling at 50 miles per hour on a wet uphill grade is given by the formula 

(a) Evaluate D(0.05) and interpret the result. 

(b) Describe what happens to the braking distance as the hill becomes steeper. Does this agree with your driving experience? 

(c) Estimate the grade associated with a braking distance of 220 feet.

Transcribed Image Text:

D(x) = 2500 30(0.3 + x)