Question

can anyone help me with this question? the function d(s)=0.0056s^2 +0.14s models the stopping distance of a car, d(s), in metres, and the speed, s, in kilometres per hour. What is the speed when the stopping distance is 7m? Use a graph to solve.

Answer 1

plug your information into the equation (hard to graph stuff on here):

7 = .0056s^2 +.14s

0 = .0056s^2 + .14s -7

either factor or use the quadratic formula to solve.

Answer 2

thanks, but i dont know what to factor out in the second equation, thats where i got stuck

Answer 3

thinking.....(12% loaded).....

Answer 4

if I did it right, and thats a BIG if... s = 28

better plug it in to double check...

Answer 5

alright, checking

Answer 6

ack!! not correct....

Answer 7

how did u get it? im so lost :p

Answer 8

lol .... I just plugged it into the quadratic formula but made a mistake somewhere... gonna try it again :)

Answer 9

sounds good : )

Answer 10

lets try 25 :)

Answer 11

25 works good :)

Answer 12

alright, thank you (: