A/B In the figure, we have chosen, for convenience, the axes rye to be parallel to the axes r'y'z', but it should be clear that one could have non-parallel translating axes The position vector rA/B defines the position of A with respect to point B in the reference frame x'y'z' The subscript notation"A/B"means"A relative to B". The positions of A and B relative to the absolute frame are given by the vectors TA and rB, respectively. Thus, we have If we derive this expression with respect to time, we obtain TA=TB+TA/B which relates the absolute velocities uA and ub to the relative velocity of A as observed by B. Differentiating again, we obtain an analogous expression for the accelerations TA=rB+r LA/B· If we reverse the roles of A and B and attach the reference frame z'y'z' to a, then we can observe b from A B/A The same arguments as before will give us rB=TA+rB/A,In the figure, we have chosen, for convenience, the axes xyz to be parallel to the axes x ′y ′ z ′ , but it should be clear that one could have non-parallel translating axes. The position vector rA/B defines the position of A with respect to point B in the reference frame x’y’z’. The subscript notation“A/B” means “A relative to B”. The positions of A and B relative to the absolute frame are given by the vectors rA and rB, respectively. Thus, we have rA = rB + rA/B . If we derive this expression with respect to time, we obtain r˙ A = r˙ B + r˙ A/B or vA = vB + vA/B , which relates the absolute velocities vA and vB to the relative velocity of A as observed by B. Differentiating again, we obtain an analogous expression for the accelerations, r¨A = r¨B + r¨A/B or aA = aB + aA/B . If we reverse the roles of A and B and attach the reference frame x ′y ′ z ′ to A, then we can observe B from A. The same arguments as before will give us, rB = rA + rB/A, vB = vA + vB/A, aB = aA + aB/A . 2