text: f=ma\n1st thing is it Einstein's law of motion or new ton's any way:\n\nwe kw that\na=v/t^2\n\nand E=mc^2\n\nc is velocity~~ square of speed of light\n\nnw compare the two!\n\nwithout any source of force there is absolutely no motion!\nbut a substance suppressing or stoping motion occurs when an equal and opposite force is applied!