i can see the point you are trying to make, but it is inherently flawed. the following has not been adjusted for time travel. timetravel in itself breaks many laws of physics. firstly: THE LAW OF CONSERVATION OF MOMENTUM. In a system with no net outside forces acting on it, momentum is conserved. Unless time travel somehow slows the car down by imparting a force to it, it must keep the same momentum before time travel as after time travel. This means it has the same "velocity" after time travel as it did before time travel. The velocity of an object is a property of it that it possesses at any one time. If you took an object from where it is and moved it instantly to another place (or time), all properties should stay the same, including velocity. This would especially apply to wormhole time travel, which I assume is used my the Doc's car. secondly: THE LAW OF CONSERVATION OF ENERGY. If the car enters the time travel vortex or whatever you want to believe, it has a certain kinetic energy. Quite a bit actually. This cannot simply disappear. It must be transfered to something else, which it doesn't seem to, or stay as it is. thirdly: LACK OF OBSERVATION. The scientific method requires observation. Have you ever seen a car stop after time travel? No? What are you basing your "theory" on? fourthly: OCHAM'S RAZOR. If a car is shown to keep it's speed after time travel, it does. Anything else just makes it more complicated. The simplest solution is usually the best. Ordinary (gradual not instantaneous like the doc's car) time travel and spatial travel are directly linked via Einstein's General Relativity. If a time traveller in such a case can only slow down (in time) relative to an observer outside his frame of reference as he increses his speed to c. At c (hypothetically) all his energy is being used to travel through space, and none is used to travel through time, thus he would be effectively frozen. If one were to go faster than c, it could be possible to go backward in time, but of course this is impossible. Without a time frame to increase one's speed in, one cannot accelerate past c. As someone stated before, finding just one fault in the movie is hardly believable. Apart from the NUMEROUS UTTERLY STUPID paradoxes that spring forth, some things just don't make any sense. Like newspapers changing. SLOWLY. Actually most of the paradoxes can be solved by the mulitple universes theory that is introduced by the Doc in either the 3rd or the 2nd movie. In such a reality it is indeed possible to kill your own grandmother before you were born. The universe that you are now in does not contain you getting born, but you come from a different one where all is well. However, Back to the Future does a poor job at implementing this concept, making most of the movie gibberish to someone with a hlafway decent knowledge of astrophysics and philosophy. I would like to also make a point on your "BACON CURES CANCER and AIDS! " comment. Excessive red beat consumption has been shown to actually increase the chance of bowel cancer. Also, excessive meat and fat consumption would lead to an imbalanced diet, which lowers the immune system and in no way helps cure anything.