Translational motion is similar to translation of a single particle. The differences being you are dealing with many particles. To sum it up, for a rigid body to be considered to have translation motion a line segment between two particles within the rigid body must remain parallel to each other as the rigid body goes from point A to point B. This applies to any type of path, whether it is a straight line, or the path has a curve to it. As long as the above statement holds true, than the rigid body has translational motion. Refer to the figure below.

To determine the position of one particle in respect to another particle within a rigid body equation 1 would be used.

**(Eq 1)** $r_B=r_A+r_{B/A}$

Notice from equation 1, the position of one particle in comparison to another particle can differ depending on where those two particles are located within the rigid body. However, velocity and acceleration for translational motion will be the same for all particles within the rigid body.

**(Eq 2) ** $V_B = V_A$

**(Eq 3)** $a_B=a_A$