英語翻譯
The stopping distance of a car is the number of feet that the car travels after the driver starts applying the brakes.The stopping distance of a certain car is directly proportional to the square of the speed of ther car,in miles per hour,at the rime the brakes are first applied.If the car's stopping distance for an initial speed of 20 miles per hour is 17 feet,what is its stopping distance for an initial speed of 40 miles per hour?