Four uniform spheres, with masses mA = 150 kg, mB = 410 kg, mC = 590 kg, and mD = 310 kg, have (x, y) coordinates of (0, 37 cm), (0, 0), (−86 cm, 0), and (32 cm, 0), respectively. In unit-vector notation, what is the net gravitational force on sphere B due to the other spheres?