A 0.7-lb particle is located at the position r₁ = 2i + 3j + k ft and has the velocity v₁ = i + j + 2k ft/sec at time t = 0. If the particle is acted upon by a single force which has the moment MO = (4 + 2t)i + (3 − t₂) j + 5k lb-ft about the origin O of the coordinate system in use, determine the angular momentum about O of the particle when t = 4 sec.