PreCalculus
posted by Becky .
An Alfa Romeo going at 70 mph requires 169 feet to stop. Assuming that the stopping distance is proportional to the square of velocity, find the stopping distances required by an Alfa Romeo going at 35 mph and at 140 mph (its top speed).

d = kv^2
169 = k*70^2
k = 169/4900
so, d = 169/4900 v^2
plug in v=35 and 140