If the speed of a car is doubled but the brakes apply the same force, the distance required to stop the car changes by a factor of
A) ¼.
B) ½.
C) 1.
D) 2.
E) 4.

Question

Quizplus · Accepted Answer

The distance required to stop a car is directly proportional to the square of its speed, according to the formula d = v^2/2a, where d is the stopping distance, v is the speed, and a is the deceleration due to the brakes. If the speed is doubled, the distance will increase by a factor of (2^2) = 4. Therefore, the correct choice is E.

If the Speed of a Car Is Doubled but the Brakes