Fill in the forces clamping two objects together and shearing them sideways, and give the coefficient of friction between them. In the orange box, the calc will determine if there is any net slipping force that will overcome friction and cause the objects to slide past each other.
Representative coefficients of friction include: wood-on-wood (~0.3); acrylic-on-acrylic (~0.8); steel-on-steel (~0.6); teflon-on-teflon (~0.04).