The bearings of a shaft at A and B are 5 m apart the shaft carries three eccentric masses C, D and E which are 160 kg, 170 kg and 85 kg respectively. The respective eccentricity of each mass, measured from the axis of rotation is 0.5 cm, 0.3 cm and 0.6 cm, and the distance from A is 1.3 m, 3 m and 4 m respectively. Determine the angular position of each mass with respect to C, so that no dynamic force is exerted at B, and also find the dynamic force at A for this arrangement when the shaft runs at 100 rpm.