Beginning drivers soon learn that bringing an automobile to a stop requires greater dist...

Beginning drivers soon learn that bringing an automobile to a stop requires greater distances for higher speeds. A formula that approximates the stopping distance under normal driving conditions is

where v = speed of the auto in miles per hour and d 5 distance in feet required to bring the auto to a stop.

(a) Find the stopping distance of an auto traveling 30 mph.

(b) Find the stopping distance of an auto traveling 60 mph.