I NEED HELP FAST. The distance it takes a truck to stop can be modeled by the function d(v)= 2.15v^2/64.4f d= stopping distance in feet v = initial velocity in miles per hour f = a constant related to friction When the truck's initial velocity on dry pavement is 40 mph, its stopping distance is 138 ft. Determine the value of f, rounded to the nearest hundredth. f= 0.39 Choose the quadratic model for the situation.???