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Cold things fall and hot things rise. If I drop 2 identical objects, 1 cold and 1 hot, will they fall at the same rate or will the cold one hit the floor first?
What about drag ?If the spheres were ball bearings, one heated red hot (+500oC), there would be transfer of heat from the hot ball to the air it was travelling through. The heated air would expand and have lower density which would reduce ...sorry, you cannot view external links. To see them, please
REGISTER or LOGIN "In physics, buoyancy (pronounced /ˈbɔɪ.ənsi/) is an upward acting force, caused by fluid pressure, that opposes an object's weight. If the object is either less dense than the liquid or is shaped appropriately (as in a boat), the force can keep the object afloat. This can occur only in a reference frame which either has a gravitational field or is accelerating due to a force other than gravity defining a "downward" direction (that is, a non-inertial reference frame). In a situation of fluid statics, the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body  This is the force that enables the object to float"You can heat a still object, (object at rest), all day long and it may never float, and if so it can not be associated to have buoyancy.
Wouldn't the material of the (+500 deg C) ball expand from the heat, increasing the area of drag?As it transfers the heat to the air around it, that air needs to displace the cooler air around it. Taking into account, these other factors, wouldn't this negate the drag theory and both fall at the same rate of speed
Quote from: tommya300 on 06/10/2010 13:24:12Wouldn't the material of the (+500 deg C) ball expand from the heat, increasing the area of drag?As it transfers the heat to the air around it, that air needs to displace the cooler air around it. Taking into account, these other factors, wouldn't this negate the drag theory and both fall at the same rate of speed Without making any computations? Are you a genius? 
Just askingIs that being reasonable?
Quote from: tommya300 on 08/10/2010 19:54:24Just askingIs that being reasonable? Don't know the exact meaning of "reasonable" not being very aknowledged with english, I can only say that it's "possible" but it depends on the object. For an iron ball (solid) I would bet on the fact the increased sectional area effect is less than the reduced density of the air, that is, the hot one would fall faster. With a hollow solid ball, it's another story, the increased dimensions for thermal expansion could be the dominant factor, but it depends on the total density of the ball: if the walls are very thin, you can be sure that the hot one would fall slower.