# Relationship of Two Particles

Two particles can be related to each other with a relative position, velocity, or acceleration at an instant in time. To calculate the relative position, velocity, or acceleration the following equations would be used.

(Eq 1)  $r_B=r_A+r_{B/A}$

(Eq 2)  $v_B=v_A+v_{B/A}$

(Eq 3) $a_B=a+a_{B/A}$

In many cases these types of problems will have motion in multiple directions. To solve these types of problems refer to the example below.