# Torque from Newton’s Laws

Is is possible to predict the motion of rigid bodies only in terms of Newton’s laws of motion without torque (for example by using the system of particles model)?

For instance, if there was a rod of length ‘l’ attached to a hinge, and a force ‘F’ was applied (perpendicular to the rod) a distance ‘r’ away from the hinge, then can the rod be broken up into infinitesimal masses (particles) then work out the internal and external forces on the rod (forces on each particle) to predict its angular acceleration. Then from this prediction maybe the torque=(moment of inertia)*(angular acceleration) relationship can be derived in terms of Newton’s laws.

• The laws of motion of rigid bodies or laws of rotational dynamics follow from Newton's laws. – SRS Apr 7 at 8:46