contestada

the braking distance D in feet required to stop a car traveling x miles per hour on dry , level pavement can be approximated by D=1/9x^2

Respuesta :

 We can find as follows 
x D=x^2/9 
speed braking distance 
mph in feet 
20 44.44 
60 400.00 

b) x^2/9=16 
x^2=144 
x=12 mph