But, is dependent on Reynolds number, which is not known. In such cease, iteration may be required. Assume that the flow is turbulent for the large–size sphere. for flow of a fluid past a sphere is approximately 0.2 (you may like to confirm the data from the graph available in the text)
Therefore,
Substituting,
= 21 m/s >> check Reynolds number
For this Reynolds number, is better approximated at Therefore, is re-calculated as . Re–check, which is more accurate than the previous case. For , answer is m/s.
is dependent on Reynolds number, which is not known. In such cease, iteration may be required. Assume that the flow is turbulent for the large–size sphere.
= 21 m/s >> check Reynolds number 
Therefore, 
. Re–check, 
which is more accurate than the previous case. For 
, answer is 
m/s. 
