On the motion of a rigid body on a plane
About the Teaching of Plane Motion of Rigid Bodies
In this paper, we discuss a couple of problems which are typically used in basic physics courses, in order to highlight some aspects related to rigid body motion which are not usually well understood by physics students.The first problem is a pendulum composed of a rod and disk.The angular frequency of the pendulum is calculated in two situations : disk fixed to the rod and disk freeto spin.A detailed explanation of the change in the angular frequency from onecase to another is given.The second problem is a ladder which slides touching a frictionless surface.We use this problem to highlight the fact that the contact forces applied by the surface perform translational and rotational work despite that the total mechanical energy of the ladder is conserved.
