Four uniform spheres having masses mA = 550 kg, mB = 200 kg, mC = 1800 kg and mD = 100 kg, encompass (x, y) coordinates of (0, 50 cm), (0, 0), (-80 cm, 0) and (40 cm, 0), correspondingly. Find out the total gravitational force on sphere B due to the other spheres?