A 900-lb space vehicle traveling with a velocity v0 = (1500 ft/s)k passes through the origin O. Explosive charges then separate the vehicle into three parts A, B, and C, with masses of 150 lb, 300 lb, and 450 lb, respectively. Knowing that shortly thereafter the positions of the three parts are, respectively, A(250, 250, 2250), B (600, 1300, 3200), and C (-475, -950, 1900), where the coordinates are expressed in ft, that the velocity of B is vB = (500 ft/s)i + (1100 ft/s)j + (2100 ft/s)k, and that the x component of the velocity of C is -400 ft/s, determine the velocity of part A.