Relative Motion

Relative velocity of A w.r.t. B => A observed from B and B is stationary
$\ov{V_{A|B}} =\ov{V_{A}} – \ov{V_{B}}$



∙Two particles, velocities parallel
Same direction:

$|V_{A|B}| = v_A – v_B$ in magnitude

Opposite direction:
$|V_{A|B}| = v_A + v_B$ in magnitude



∙ Two velocities perpendicular
$|V_{A|B}| = √{{V^2_A} + {V^2_B}}$

$tanθ = {V_B}/{V_A}$