# Balancing - Mechanical Engineering (MCQ) questions and answers

1)   Which of the following conditions should be satisfied for static balancing?

1. Dynamic forces acting on the system should be zero
2. Couple acting on the system due to dynamic force should be zero
3. Centrifugal forces acting on the system should be zero
4. Couple acting on the system due to centrifugal forces should be zero

a. Condition 1 and condition 2
b. Condition 1 and condition 3
c. Condition 3 and condition 4
d. All of the above
 Answer  Explanation ANSWER: Condition 1 and condition 3 Explanation: No explanation is available for this question!

2)   The unbalanced primary couple caused due to reciprocating mass of each cylinder is given as

a. mrlω2 cos θ
b. mrlω (cos θ / n)
c. mrlω2 cos 2θ
d. mrω2 cos 2θ
 Answer  Explanation ANSWER: mrlω2 cos θ Explanation: No explanation is available for this question!

3)   Which of the following statements is/are true primary/secondary couple?

1. Secondary couple does not act on V engine
2. Primary couple acts on V engine
3. Secondary couple acts on reciprocating masses of multi-cylinder inline engines
4. Primary couple acts on reciprocating masses of multi-cylinder inline engines

a. 1 and 2
b. 2, 3 and 4
c. 1, 3 and 4
d. All of the above
 Answer  Explanation ANSWER: 1, 3 and 4 Explanation: No explanation is available for this question!

4)   Which of the following conditions should be satisfied for complete balancing of multi-cylinder inline engines?

a. Primary couples should be balanced
b. Secondary couples should be balanced
c. Both a. and b.
d. None of the above
 Answer  Explanation ANSWER: Both a. and b. Explanation: No explanation is available for this question!

5)   At which angle primary unbalanced force in reciprocating engine mechanism is maximum?

a. 0o
b. 90o
c. 360o
d. All of the above
 Answer  Explanation ANSWER: 0o Explanation: No explanation is available for this question!

6)   Secondary force in reciprocating engine mechanism is caused due to _______

a. S.H.M. of reciprocating parts
b. oscillation of reciprocating parts
c. obliquity of arrangement of reciprocating parts
d. all of the above
 Answer  Explanation ANSWER: obliquity of arrangement of reciprocating parts Explanation: No explanation is available for this question!

7)   The unbalanced force caused due to reciprocating mass is given by the equation

a. mrω2 sin θ + mrω2 (sin 2θ/n)
b. mrω2 sin θ + mrω2 (cos 2θ/n)
c. mrω2 cos θ + mrω2 (cos 2θ/n)
d. mrω2 (sin θ + sin 2θ/n)
 Answer  Explanation ANSWER: mrω2 cos θ + mrω2 (cos 2θ/n) Explanation: No explanation is available for this question!

8)   Determine magnitude of balancing mass required if 250 mm is the radius of rotation. Masses of A, B and C are 300 kg, 250 kg and 100 kg which have radii of rotation as  50 mm, 80 mm and 100 mm respectively . The angles between the consecutive masses are 110o and 270o respectively.

a. 45.36 kg
b. 47.98 kg
c. 40.50 kg
d. None of the above
 Answer  Explanation ANSWER: 47.98 kg Explanation: No explanation is available for this question!

9)   Which of the following factors are not responsible for unbalancing in rotating systems?

a. Errors
b. Tolerances
c. Shape of the rotor
d. None of the above
 Answer  Explanation ANSWER: None of the above Explanation: No explanation is available for this question!