A student conducts several experiments to measure the drag force on a translating sphere of radius d with speed U in a viscous fluid, of dynamic viscosity n and density p, tank as shown below. He moves the sphere slowly with a constant speed to ensure that the inertial forces are much smaller than the viscous forces. He records the measured forces as function of the speed U by varying fluid viscosity, sphere diameter and speed. fluid ρ, η U 400 300 200 27, 2d 27, d sphere d 100 n. d 3 U He observes from the plot of the change of F given above that the drag force is linearly dependent on U, d and 7. He claims that F = AnUd with A being the coefficient of the dependence. I. The dimenison of A is 1. II. The Reynolds number of this flow is unity. III. The traction on the sphere surface is F. IV. If the sphere does not translate, the vertical component of the traction acting on the surface of sphere due to fluid is zero. V. The same force could not be computed using Euler's equations of motion. Which of the above statements are true?