Problem 29 (Similarity). Two railroad cars are at rest on two horizontal frictionless tracks. The mass of the first car is mị and the mass of the second car is

m2 = 3m1. Each car is pushed with the same horizontal force of F for the same time T. At the end of this time, the kinetic energy of the lighter car is K1. What is the kinetic energy of the heavier car K2? (а) ЗК] \text { (b) } \sqrt{3} K_{1} \text { (c) } K_{1} / \sqrt{3} (d) K1/3 (e) None of these