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

Dynamics of Machinery (3151911) MCQs

MCQs of Balancing of Reciprocating Masses

Showing 41 to 49 out of 49 Questions

41.

When the primary direct crank of a reciprocating engine makes an angle θ with the line of stroke, then the secondary direct crank will make an angle of ________ with the line of stroke.

(a)	θ/2
(b)	θ
(c)	2θ
(d)	4θ

42.

For the secondary balancing of the engine, which of the condition is necessary?

(a)	Secondary force polygon must be close
(b)	Secondary force polygon must be open
(c)	Primary force polygon must be close
(d)	Primary force polygon must be open

43.

Which of the following statement is correct?

(a)	In any engine, 100% of the reciprocating masses can be balanced dynamically
(b)	In the case of balancing of the multicylinder engine, the value of secondary force is higher than the value of the primary force
(c)	In the case of balancing of multi mass rotating systems, dynamic balancing can be directly started without static balancing done to the system
(d)	none of these

44.

In a multicylinder inline engine, each imaginary secondary crank with a mass attached to the crankpin is inclined to the line of a stroke at which angle?

(a)	Twice the angle of the crank
(b)	Half the angle of the crank
(c)	Thrice the angle of the crank
(d)	Four times the angle of the crank

45.

Length of the crank shaft is maximum in

(a)	V-type engine
(b)	inline engine
(c)	radial engine
(d)	opposite cylinder engine

46.

The resultant primary unbalanced force due to inertia of reciprocating parts in a V-engine is given by (where m = Mass of reciprocating parts, ω = Angular speed of crank, r = Radius of the crank, and = Angle of inclination of the crank with the line of stroke

(a)	$2 m r ω^{2} \sqrt{{(\cos^{2} α \cos θ)}^{2} + {(\sin^{2} α \sin θ)}^{2}}$
(b)	$2 m r ω^{2} \sqrt{{(\cos^{2} α \cos θ)}^{2} - {(\sin^{2} α \sin θ)}^{2}}$
(c)	$2 m r ω^{2} \sqrt{{(\cos^{2} θ \cos α)}^{2} + {(\sin^{2} θ \sin α)}^{2}}$
(d)	$2 m r ω^{2} \sqrt{{(\cos^{2} θ \cos α)}^{2} - {(\sin^{2} θ \sin α)}^{2}}$

47.

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

(a)	$\frac{m r ω^{2}}{4 n} \sqrt{{(\cos α \cos 2 α \cos 2 θ)}^{2} + {(\sin α \sin 2 α \sin 2 θ)}^{2}}$
(b)	$\frac{m r ω^{2}}{2 n} \sqrt{{(\cos α \cos 2 α \cos 2 θ)}^{2} + {(\sin α \sin 2 α \sin 2 θ)}^{2}}$
(c)	$\frac{2 m r ω^{2}}{n} \sqrt{{(\cos α \cos 2 α \cos 2 θ)}^{2} + {(\sin α \sin 2 α \sin 2 θ)}^{2}}$
(d)	$\frac{m r ω^{2}}{n} \sqrt{{(\cos α \cos 2 α \cos 2 θ)}^{2} + {(\sin α \sin 2 α \sin 2 θ)}^{2}}$

48.

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

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

49.

The V-twin engine has the cylinder axes at 90 degrees and the connecting rods operate a common crank. The reciprocating mass per cylinder is 11.5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of the maximum resultant secondary force in Newtons?

(a)	736
(b)	836
(c)	936
(d)	636

Showing 41 to 49 out of 49 Questions