Multiscale simulations of molecular systems such as proteins, DNAs, and RNAs are implemented using models with different resolutions ranging from a fully atomistic model to coarse-grained molecules, up to a continuum level system descriptions. For such simulations, pairwise force calculation is a serious bottleneck which can impose a prohibitive amount of computational load on the simulation if not performed wisely. Herein, a novel method is presented to approximate the resultant force and the associated moment for long-range particle-body and body-body interactions applicable to multiresolution coarse-grained simulation of biopolymers. The resultant moment is due to the fact that the net force does not necessarily act through the center of mass of the body. This moment is neglected in bead-based coarse models which use particle dynamics to form the equations of motion of each large spherical pseudo-atom. The presented method significantly reduces the cost of the force field calculations specially in multiscale models which contain rigid subdomains.