When a door is pushed at the edge with a force F, a torque is exerted on the door of magnitude Fr (r=level arm). The torque compel the door to rotate at an angular acceleration alpha. So the torque=(moment of inertia)*(angular acceleration). Now the question is : is Fr=(moment of inertia)*(angular acceleration)? I think it is incorrect for "torque=I*alpha" is derived by summing Fr of every single point mass over the whole body. Your response will broaden my view toward physics.