Every year, the Spring Festival travel rush peak will encounter similar problems, that is, "the return trip of Spring Festival travel rush peak encounters rain and snow, and the speed limit of high-sp

Every year, the Spring Festival travel rush peak will encounter similar problems, that is, "the return trip of Spring Festival travel rush peak encounters rain and snow, and the speed limit of high-speed high-speed rail is closed", in which "speed limit" can be ( A, inertia refers to the nature of the object to keep the original state of motion unchanged, inertia is related to the quality, has nothing to do with the speed of the object, this option is not correct;

B, kinetic energy refers to the energy that an object has due to movement, which is related to the mass and speed of the object, so speed limit can reduce the kinetic energy of the train. This option is correct;

C, friction is related to the pressure and roughness of the contact surface, has nothing to do with the speed of the object, this option is not correct;

D, the difficulty of changing the train state depends on the quality of the train, and has nothing to do with the speed of the train. This option is incorrect.

So choose B.