Theory of Machines Online Test - Set 05 - ObjectiveBooks

Theory of Machines Online Test - Set 05

Practice Test: Question Set - 05

1. Lower pairs are those which have
    (A) Point or line contact between the two elements when in motion
    (B) Surface contact between the two elements when in motion
    (C) Elements of pairs not held together mechanically
    (D) Two elements that permit relative motion

2. 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

3. The Coriolis component of acceleration leads the sliding velocity by
    (A) 45°
    (B) 90°
    (C) 135°
    (D) 180°

4. The power of a Porter governor is equal to
    (A) [c²/(1 + 2c)] (m + M) g.h
    (B) [2c²/(1 + 2c)] (m + M) g.h
    (C) [3c²/(1 + 2c)] (m + M) g.h
    (D) [4c²/(1 + 2c)] (m + M) g.h

5. In the two rotor system as shown in the below figure (I₁ < I₂), a node of vibration is situated

    (A) Between I₁, and I₂ but nearer I₁
    (B) Between I₁, and I₂ but nearer to I₂
    (C) Exactly in the middle of the shaft
    (D) Nearer to I₁ but outside

6. Whitworth quick return mechanism is obtained by inversion of
    (A) Slider crank mechanism
    (B) Kinematic chain
    (C) Five link mechanism
    (D) Roller cam mechanism

7. In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The minimum length of the coupler will be
    (A) 45 mm
    (B) Slightly less than 45 mm
    (C) Slightly more than 45 mm
    (D) 95 mm

8. The Grubler's criterion for determining the degrees of freedom (n) of a mechanism having plane motion is (where l = Number of links, and j = Number of binary joints)
    (A) n = (l -1) - j
    (B) n = 2(l - 1) - 2j
    (C) n = 3(l - 1) - 2j
    (D) n = 4(l - 1) - 3j

9. For dynamic balancing of a shaft
    (A) The net dynamic force acting on the shaft is equal to zero
    (B) The net couple due to the dynamic forces acting on the shaft is equal to zero
    (C) Both (A) and (B)
    (D) None of the above

10. The periodic time of a compound pendulum is __________ when the distance between the point of suspension and the center of gravity is equal to the radius of gyration of the body about its center of gravity.
    (A) Zero
    (B) Minimum
    (C) Maximum
    (D) None of these

11. Which is the false statement about the properties of instantaneous center?
    (A) At the instantaneous center of rotation, one rigid link rotates instantaneously relative to another for the configuration of mechanism considered
    (B) The two rigid links have no linear velocities relative to each other at the instantaneous center
    (C) The two rigid links which have no linear velocity relative to each other at this center have the same linear velocity to the third rigid link
    (D) The double center can be denoted either by O2\ or O12, but proper selection should be made

12. 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

13. The distance by which the __________ of the D-slide valve overlaps the steam port is called exhaust lap.
    (A) Inner edge
    (B) Outer edge
    (C) Corners
    (D) None of these

14. In a Hartnell governor, the stiffness of the spring is given by (where S1 and S2 = Spring forces exerted on the sleeve at max. and min. radii of rotation, and h = Compression of the spring)
    (A) (S₁ + S₂) / h
    (B) (S₁ - S₂) / h
    (C) (S₁ + S₂) / 2h
    (D) (S₁ - S₂) / 2h

15. The number of centers in a crank driven slider crank mechanism is
    (A) 0
    (B) 2
    (C) 4
    (D) 6

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