What frequency do you hear if you are traveling at 15 m/s toward a train with a 750 Hz whistle? The train is moving away from you at 25 m/s and the
temperature is 15° C.

energy can be converted from one form to another, but it cannot be created or destroyed in ordinary chemical or physical means. do not understand what you are asking but hope this

reserve is the answer

that would be because of both gravity and friction. so     c