(adsbygoogle = window.adsbygoogle || []).push({}); Drag Coefficient out by a factor of 10, can anyone help??

Im doing an experiment on the drag of a sphere and am trying to work out the drag coefficient. From looking at data online this should be around 0.5 (its a smooth sphere). Using a wind tunnel I measured the drag for various sizes of spheres and wind speeds. An example of one of my results is

Drag - 0.68N

Wind Speed - 7.8m/s

Radius of Sphere - 0.0371m

Then, using the formula

Drag Coefficent = (2 x Drag) / Area x Wind Speed^2 x Density of Air

Having measured the room temperature to be 22 degrees celcius I took the density of air to be 1.204kg/m^3 and the projected frontal area was calculated using pi x r^2

But this equals 5.039!!!! so could anyone point out where im going wrong?? Im 90% sure all of my values are correct. Thanks in advance for any help :)

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# Drag Coefficient out by a factor of 10, can anyone help?

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