Figure 4.

Normalized drag and torque coefficients for colloid motion on the surface of a thin film atop a solid substrate: (a) drag coefficient ($k_D^{t\text{'}}$) for a translating colloid, (b) coefficient for the torque generated by a translating colloid ($k_T^{t\text{'}}$) or drag coefficient generated for a rotating colloid ($k_D^{r\text{'}}$), (c) coefficient of resistive torque ($k_T^{r\text{'}}$) for a rotating colloid all as a function of film thickness and slip length equal to 0.01 and normalized by value atop a semi-infinte medium, and (d) Normalized coefficients of resistive torque (${\hat{k}}_T^r$, scaled by value completely immersed in an infinite medium) as function of film thickness for a rotating colloid for two different slip lengths λ/a = 0.01 or 0.05 as a function of thickness. The contact angle is π/2.