Food Rheology and Texture

Tomato paste follows the Herschel-Bulkley model with yield stress $\tau_0 = 50\text{ Pa}$, consistency coefficient $K = 20\text{ Pa}\cdot\text{s}^{0.5}$, and flow index $n = 0.5$. At shear rate $\dot{\gamma} = 4.0\text{ s}^{-1}$ (where $4.0^{0.5} = 2.0$), the shear stress $\tau = 50 + 20(2.0) = 50 + 40$ in Pa is: