Answer:
40 mph
Step-by-step explanation:
To find the maximum speed at which the car can travel, as the distance it requires to stop is 168 feet, we just need to use the value of d = 168 in the equation, and then find the value of s:
168 = 0.05s^2 + 2.2s
0.05s^2 + 2.2s - 168 = 0
Using Bhaskara's formula: we have:
Delta = 2.2^2 + 4*0.05*168 = 38.44
sqrt(Delta) = 6.2
s1 = (-2.2 + 6.2)/0.1 = 40 mph
s2 = (-2.2 - 6.2)/0.1 = -84 mph (a negative value does not make sense as 's' is the speed of the car)
So the maximum speed of the car is 40 mph
