Two grains of space dust in a proto-planetary disk impact each other and stick together to form a larger chunk of space dust. Before the collision, grain one, with mass 4.60×10−9 kg, has a velocity of (3.00, 9.00) m/s and grain two, with mass 2.40×10−9 kg has a velocity of (0, 18.0) m/s. Find the final velocity of the resulting chunk of space dust in rectangular vector notation.