Loading ...In physics , very fine particulate such as smoke tends to remain aloft . Extremely fine powder falls very slowly , so finely ground particles probably make up the plume being blown downriver by the wind .
If one is at the edge of a cliff , and throws a stone horizontally off the cliff , the horizontal velocity does not change significantly once the rock leaves your hand ( air drag could slow it a tiny amount , which can be ignored ) . Gravity , however starts pulling the rock downward , accelerating it at a little over 32 ft. per second per second . That is , after one second it is falling at a rate of 32 ft./second . After two seconds , it is falling at 64 feet per second , after three seconds it is falling at 96 feet per second , etc.
The path the rock traces is a parabola . It keeps traveling horizontally at a fixed velocity , but vertically it falls faster and faster until it hits the ground .
If you look at the photograph closely , you see that defining parabolic shape in the outline of the collapsing building .