## Friday, 10 November 2017

### Balancing of Rotating Masses -- OBJECTIVE TYPE QUESTIONS

Balancing Of Rotating masses
Objective type questions

1. The balancing of Rotating and Reciprocating parts of the engine is necessary when it runs at
(a) Slow speed                                         (b) Medium speed
(cHigh speed                                         (d) No speed

2. Which of statements is true for static balancing of shaft,
(a) The net dynamic forces acting on the shaft is zero
(b)  The net couple due to dynamic forces acting on the shaft is zero
(c) Both (a) and (b)                          (d) None of the above statements

3. For Dynamic balancing of shaft,
(a) The net dynamic forces acting on the shaft is zero
(b)  The net couple due to dynamic forces acting on the shaft is zero
(c) Both (a) and (b)                          (d) None of the above statements

4. Which of the following statements is correct about the balancing of a mechanicalsystem?
(a) If it is under Static balance, then there will be dynamic balance too
(b)  If it is under Dynamic balance, then there will be Static balance too
(c) Both Dynamic and Static balance have to be achieved separately
(d) None of the above mentioned statements

5. A distributing mass m1 attached to a rotating shaft may be balanced by a single mass mattached in the same plane of ratation as that of m1 such that
(am1.r2 = m2.r1
(b)  m1.r1 = m2.r2
(cm1. m2 = r1.r2

6. Which of the following statements are associated inorder to have a complete balancing of the several revolving masses in different planes
(a) The resultant couple must be zero
(bThe resultant force must be zero
(c) Both resultant force and couple must be zero
(d) None of the above

7. Which of the following statements are associated with complete dynamic balancing of rotating systems?
(1) The resultant couple due to all inertia forces is zero
(2The support reactions due to forces are zero but not due to couples
(3) The system is automatically statically balanced
(4) Centre of masses of the system lies on the axis of rotation

(a) 1, 2 and 3 only           (b2, 3 and 4 only
(c) 1, 3 and 4 only           (d) 1, 2, 3 and 4