assumed two kinds surface forces math mathbf f c math body forces math mathbf f b math thus total force math mathcal f math applied body portion body expressed math mathcal f mathbf f c mathbf f b math surface forces ''surface forces'' ''contact forces'' expressed force per unit area act either bounding surface body result mechanical contact bodies imaginary internal surfaces bound portions body result mechanical interaction parts body
Applied science Engineering and technology Mechanical Engineering Continuum mechanics