r⃗_{AP} ≠ r⃗_{BP}

r⃗_{AP} = r⃗_{AB} + r⃗_{BP}

r⃗_{AP} − r⃗_{BP} = r⃗_{AB}

v⃗_{AP} − v⃗_{AB} = v⃗_{BP}

v⃗_{AP} − v⃗_{BP} = v⃗_{AB}