Question

Car 1 is driving three times faster than Car 2. Which of the following is true about the kinetic energy of Car 1 compared to Car 2?


A. Its kinetic energy is the same

B. Its kinetic energy is three times larger

C. Its kinetic energy is three times smaller

D. Its kinetic energy is nine times larger

Answer 1

The kinetic energy

$$K=\frac{mv^2}{2}.$$

Hence, if velocity of Car 1 is three times larger as Car 2, then kinetic energy Car 1 is nine times larger.

Answer D.