2. Solid state kinematics

To study the motion of a solid (S _k ) in a reference frame, we link to (S _k ) the reference frame (R _k ) and study the motion of (R _k ) in (R _i ) (figure 27 ).

Indeed, at any point of (S _k ) we can make coincide a point of (R _k ) whose kinematic elements are identical. Similarly, to study the motion of a solid (S ₂ ) relative to a solid (S ₁ ), we link to (S _1...