A shaft carries four masses: Determine angular positions

Question

A shaft carries four masses in parallel planes A, B, C and D in order. The masses at B and C are 18 kg and 12.5 kg respectively and each has an eccentricity of 6 cm. The masses at A and D have an eccentricity of 8 cm. The angle between the masses at B and C is 100⁰ and that between the masses at B and C is 100⁰ and that between the masses at B and A is 190⁰ (both angles measured in the same sense). The axial distance between the planes A and B is 10 cm and between B and C 20 cm. If the shaft is in complete dynamic balance, determine

1. the masses at A and D
2. the distance between the planes C and D.
3. the angular position of the mass at D.                                                                     

Answer 1

In a Dynamic balance system