(Q&A) This stopping distance D of a car after the brakes are applied varies directly as the sq of the speed R.?

Q: If a car traveling 40mph can stop in 90ft, now many feet will it take the same car to stop when it is trsveling 70mph?

A: The car increases the speed by (70/40) times. Which means the distance will increase by (70/40)^2 times

so the answer is (70/40)^2 * 90 = 275.625ft