The distance required for a car to stop is directly proportional to the square of its velocity. If a car can stop in 112.5 meters at 15 kilometers per hour, how many meters are needed to stop at 25 kilometers per hour?

Answer 1

d = k v^2
112.5 = k (225)
k = .5
so
d = .5 v^2
d = .5 (625) = 312.5