Problem 14    Due 2/25/00


        We wish to measure the dimensionless drag on a sphere settling
through a viscous fluid at low Reynolds numbers.  We have conducted an 
experiment with a particular sphere and have obtained the following 
results (with two sigma error limits):

        U = 0.679 cm/s +- 0.012 cm/s
        visc = 1.22p +- 0.03p (note: poise is the cgs unit of measurement 
                                of viscosity)
        a = 0.051cm +- 0.004cm (the sphere radius)
        density(sphere) = 2.40 g/cm3 +- 0.05 g/cm3
        density(fluid) = 1.215 g/cm3 +- 0.005 g/cm3
        g = 980.0 cm/s2 (no error in this value)

Using this data, calculate the dimensionless drag defined by:

Drag = U / [(density(sphere)-density(fluid))*g*a^2/visc] 

and determine the 95% confidence limits.  Is this value within 2sigma of 
the theoretical value of 2/9 found for zero Reynolds number?