Determine the relative angular settings of the four masses?

Question

A rotating shaft carries four masses A, B, C and D at radii of 10 cm, 12.5 cm, 20 cm and r cm respectively. The planes in which the masses revolve are spaced 60 cm apart. The masses B, C and D are known to be 10 kg, 5 kg and 4 kg respectively.

It is desired that the rotating shaft should be in complete dynamic balance. For this to be achieved, determine :

1. required mass A
2. the relative angular settings of the four masses, given that the angular spacing of the planes containing C and D are 118⁰ and 260⁰ respectively relative to B measured in the same sense.
3. Find the radius at which mass D is to be placed.                                                     30

 

Answer 1

To achieve dynamic balance of the rotating shaft

Note : Instead ‘B’, If reference plane should has considered at ‘D’ then it would have simplified the
problem.