Got curious through your thread at GD .. just have a question:
[quote]Originally posted by Faceman:
Quote:
Originally posted by John D Harris:
a little math:
a penny weighs 2.5g
dropping height = 10000m (about 33000 feet)
s = g/2*t^2
10000 = 10/2*t^2
t = sqrt(2000) - square root of 2000
The pennies fall for about 45 seconds
v = g*t = 10*sqrt(2000)
They reach a speed of about 450m/s
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Where did friction go ?
Because a feather takes a preeeetty long time to get down from 33000 feet, but I can assure you that it does not reach speeds like 450m/s, which if you use just your formula
would appear to be the result ...