<p>Okay… I understand when they plug into the formula or whatever but how could you figure it out if you didn’t know how to find that formula so to speak…</p>
<p>Thank You!</p>
<p>well it’s said in the problem … you have s^2/v = proportional to s2^2/v2 so you can assume that s^2/v = a (a-const). Now you should only make it not for parameters (s;v) but for the speed and the distance. In case 1 where you have s and v you should find whats the value of a. Thus put the last in case 2 so you can find out what it’s needed</p>
<p>They tell you that braking distance is proportional to the square of the speed. You have to figure out the formula for yourself. Thus, d=kv^2. Notice that you need the proportionality constant in there. Basically, when you have to create your own formula, just base it solely of the information they give you.</p>