No, the grandfather paradox would mean that the bunch of molecules will never end up turning into your present self. Sure they'll exist, but will you?

I know what the grandfather paradox is. Let's not get into the paradox firstly. Suppose you indeed go back in time and alter time in such a way that your grandfather never meets your grandmother, i.e. it needs not be murder. You will by definition cease to exist. The combination of DNA molecules that is your genetic code wouldn't exist. So yes, you cease to exist. It is that ceasing to exist part that leads to the paradox.

There aren't any laws of physics I know of, regarding about what you're talking about. But giving it more thought, there isn't any need for 'energy' to change any action, because from the point in time you were killed, you 'ceased' to exist, and thus there doesn't need to be any unravelling of your actions in the time after that event, because you never participated in the thing in the first place.

Of course this is all highly speculative, and has nothing to do with the physics of time at all.

BlueWind: speed =! force, and neither is it proportional. you're confusing acceleration and velocity

e.g. astronauts travel at some really high speed in the ISS (20,000 km/h or something relative to the surface of the Earth) but they're virtually weightless in the ISS