MCQs of Balancing of Reciprocating Masses (Dynamics of Machinery - 3151911)

Dynamics of Machinery (3151911) MCQs

MCQs of Balancing of Reciprocating Masses

Showing 1 to 10 out of 49 Questions

When the crank is at the inner dead center, in a reciprocating steam engine, then the velocity of the piston will be

(a)	minimum
(b)	zero
(c)	maximum
(d)	none of the mentioned

The unbalanced primary forces in a reciprocating engine are

(a)	balanced completely
(b)	balanced partially
(c)	balanced by secondary forces
(d)	not balanced

If the mass of the reciprocating parts is doubled, then the primary force is halved.

(a)	True
(b)	False

The acceleration of piston in a reciprocating steam engine is given by (where ω = Angular velocity of the crank, r = Radius of crank pin circle, θ = Angle turned by the crank from inner dead center and n = Ratio of length of connecting rod to the radius of the crank)

(a)	$ω . r (\sin θ + \frac{\sin 2 θ}{n})$
(b)	$ω . r (\cos θ + \frac{\cos 2 θ}{n})$
(c)	$ω^{2} . r (\sin θ + \frac{\sin 2 θ}{n})$
(d)	$ω^{2} . r (\cos θ + \frac{\cos 2 θ}{n})$

The primary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of the crank, θ = Angle of inclination of the crank with the line of stroke, and n = Ratio of the length of connecting rod to the radius of the crank)

(a)	$m r ω^{2} \sin θ$
(b)	$m r ω^{2} \cos θ$
(c)	$m r ω^{2} (\frac{\sin 2 θ}{n})$
(d)	$m r ω^{2} (\frac{\cos 2 θ}{n})$

The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of the crank, θ = Angle of inclination of the crank with the line of stroke, and n = Ratio of the length of connecting rod to the radius of the crank)

(a)	$m r ω^{2} \sin θ$
(b)	$m r ω^{2} \cos θ$
(c)	$m r ω^{2} (\frac{\sin 2 θ}{n})$
(d)	$m r ω^{2} (\frac{\cos 2 θ}{n})$

The primary unbalanced force of reciprocating masses is inversely proportional to the crank radius.

(a)	Yes
(b)	No

Which of the following statement is correct?

(a)	The primary unbalanced force is less than the secondary unbalanced force.
(b)	The primary unbalanced force is maximum twice in one revolution of the crank.
(c)	The unbalanced force due to reciprocating masses varies in magnitude and direction both.
(d)	The magnitude of swaying couple in locomotives is inversely proportional to the distance between the two-cylinder center lines.

In a reciprocating engine, usually __________ of the reciprocating masses are balanced.

(a)	one-half
(b)	two-third
(c)	three-fourth
(d)	whole

10.

The partial balancing means

(a)	balancing partially the revolving masses
(b)	balancing partially the reciprocating masses
(c)	the best balancing of engines
(d)	worst balancing of engines

Showing 1 to 10 out of 49 Questions