Sheet "spinning" -M. A Newtonian polymeric liquid of viscosity is be- ing "spun" (drawn into a sheet of small thickness before solidifying by pulling it through a chemical setting bath) in the apparatus shown in Fig. P6.6. The liquid volumetric flow rate is Q, and the sheet thicknesses atz = 0 and z = L are A and 8, respectively. The effects of gravity, inertia, and surface tension are negligible. Derive an expression for the tensile force needed to pull the filament downwards. Hint: start by assuming that the vertically downwards velocity v depends only on 2 and that the lateral velocity v, is zero. Also derive an expression for the downwards velocity v as a function of z. z=0 z=L d W Problemsfor Chapter 6 Polymer sheet Supply tank Roller 305