Dynamics of Machinery (3151911) MCQ

MCQs of Balancing of Rotating Masses

MCQ No - 1

The balancing of rotating and reciprocating parts of an engine is necessary when it runs at

(A)

slow speed 

(B)

medium speed 

(C)

high speed 

(D)

none of the mentioned


C
MCQ No - 2

The static balancing is satisfactory for low-speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because the

(A)

unbalanced couples are caused only at higher speeds

(B)

unbalanced forces are not dangerous at higher speeds

(C)

effects of unbalances are proportional to the square of the speed

(D)

effects of unbalances are directly proportional to the speed


C
MCQ No - 3

A system in dynamic balance implies that

(A)

the system is critically damped

(B)

there is no critical speed in the system

(C)

the system is also statically balanced

(D)

there will absolutely no wear of bearings


C
MCQ No - 4

A disturbing mass m1 attached to a rotating shaft may be balanced by a single mass m2 attached in the same plane of rotation as that of m1 such that

(A)

m1.r2 = m2.r

(B)

m1.r1 = m2.r2 

(C)

m1. m2 = r1.r2


B
MCQ No - 5

For dynamic balancing of a shaft,

(A)

the resultant force must be zero

(B)

the resultant couple must be zero

(C)

both the resultant force and couple must be zero


C