Schematic representation of the forces and torques acting in between the i-th and the j-th monomer at positions X_i and X_j, respectively. The common contact surface with radius r_ij is shaded in red. (a) Each individual monomer experiences external centrifugal F_cent, Coriolis F_cor, and Euler forces F_eul as a result of the aggregate’s accelerated rotation with angular velocity ω_agg. (b) The normal force F_N,ij acts normal to the contact surface of two monomers because of surface attraction and mechanical deformation with the contact pointers remaining anti-parallel n_i = –n_j. (c) The sliding force, F_S,ij, is parallel to the sliding displacement, ζ. Both F_S,ij and the corresponding sliding torque ΓS,ij work tangential to the contact surface. (d) The same is truefor the rolling of monomers within the aggregate: The rolling displacement ξ, the force F_R,ij, and the Γ_R,ij are tangential to the contact surface. (e) The twisting of monomers in contact is not associated with a net force. The resulting torque Γ_T,ij is parallel to the normal vector ϕ of the twisting. We note that the depicted quantities are not to scale since r_ij ≪ a_mon.