(b) A shaft carries three pulleys, each of mass 12 kg, in planes A, B and C, the eccentricity of the mass centres of these pulleys being 5 mm, 4 mm and 3 mm respectively. The bearings are positioned in planes L and M. The relative axial positions of these planes are shown in Figure 6 (a), and the relative angular positions of the mass centre of each of the pulleys are indicated in Figure 6 (b). The shaft rotates at 1000 rad/s. Determine the dynamic force exerted by this shaft on each of the bearings. L B C M 100 mm 100 mm Be 200 mm 100 mm 90 240 Figure Q6 a and b A (14 marks)