Originally Posted by
pacificaslim
I think you're overthinking this now. If I put on a jacket, I certainly weigh more than without it. If I unzip it and use it as a "parachute" like object to increase my air resistance and slow me down while falling out of an airplane or rolling downhill on my bike, this does not make me weigh any less (by any commonly accepted concept of the word "weight"). I go slower, but I weigh more, than I would without that weight on my body. That's all I was saying: that adding weight in a way that increases air resistance will not result in a faster fall - and therefore, if we want to be totally accurate, we can not hold that falling speed is dependent on weight, (since it is not always so).
It is dependant on all of the variables listed in the equation that Shimagnolo posted, among those is weight (mass * gravity). Some of those are pretty constant, such as gravity and the density of air - they do vary by altitude but just slightly. That means you're left with mass, drag coefficient and surface area all of which the speed is
dependant on.
If something is
independant of a variable, changing it and nothing else will not affect the end result. Falling speed is independant of the color of an object. A skydiver's falling speed is independent of a skydiver's music preference. Falling speed is dependant on mass, drag and surface area. You can also add in there friction from the bikes moving parts (bearings, chain, tires etc.)