A 1000-kg car traveling at 70 m/s takes 3 m to stop under full braking. The same car under similar road conditions, traveling at 140 m/s, takes ______________ m to stop under full braking.
A) 6
B) 1
C) 3
D) 12
E) 11

Question

Quizplus · Accepted Answer

The stopping distance under braking is directly proportional to the square of the velocity. When the velocity doubles (from 70 m/s to 140 m/s), the stopping distance becomes four times larger (3 m x 4 = 12 m).

A 1000-Kg Car Traveling at 70 M/s Takes 3 M