A protein has a translational diffusion coefficient of D = 6.9 × 10⁻¹¹ m² s⁻¹ at T = 298 K. The solvent viscosity is η = 0.891 × 10⁻³ kg m⁻¹ s⁻¹.
Part A: Assuming the molecule is approximately spherical, calculate the coefficient of translational friction. Give your answer in units of kg/s.
Part B: Calculate the root-mean-square displacement of the protein after one millisecond.