4 Purely rotational motion Any point moves around one same axis. Axis of rotation 5. Torque on an axis The torque about a given axis is defined as: z=R1F=RF⊥ T=RFSing =R×F4 Purely Rotational motion Any point moves around one same axis. Axis of rotation  = R F 5. Torque on an axis  = RF sin  = R⊥ F The torque about a given axis is defined as: = RF⊥