Car A has triple the mass and speed of Car B. What is the ratio of the kinetic energy of Car A to Car B?

Question

A. 3

B. 6

C. 9

D. 27

Answer 1

Kinetic Energy is defined by 1/2 m v²

K. Energy_{A =} 1/2 * 3m * (3V)^2. = 1/2 x 27mV²

(We can omit 1/2`s and m`s and V`s as they are present in both equations. )

K.Energy_{B =} 1/2 * m * V^{2. =} 1/2 mV²

KE_A / KE_B = 27mV²/ mV^2. = 27