Theory of Machines Mechanical Engineering Objective Questions with Answers - Set 11 - ObjectiveBooks

# Practice Test: Question Set - 11

1. The frictional torque transmitted in a flat collar bearing, considering uniform pressure, is (where r₁ and r₂ = External and internal radii of collar respectively)
(A) (1/2). μ W (r₁ + r₂)
(B) (2/3). μ W (r₁ + r₂)
(C) (1/2). μ W  [(r₁³ - r₂³)/(r₁² - r₂²)]
(D) (2/3). μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

2. In a flat collar pivot bearing, the moment due to friction is proportional to
(A) (r₁² - r₂²)/(r₁ - r₂)
(B) (r₁² - r₂²)/(r₁ + r₂)
(C) (r₁³ - r₂³)/(r₁² - r₂²)
(D) (r₁³ - r₂³)/(r₁ - r₂)

3. The cam and follower is an example of
(A) Sliding pair
(B) Rolling pair
(C) Lower pair
(D) Higher pair

4. When a shaking force is transmitted through the springs, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than
(A) 0.25
(B) 0.5
(C) 1
(D) 2

5. Angle of dwell of cam is defined as the angle
(A) During which the follower returns to its initial position
(B) Of rotation of the cam for definite displacement of the follower
(C) Through which the cam rotates during the period in which the follower remains in the highest position
(D) Moved by the cam from the instant the follower begins to rise, till it reaches its highest position

6. Rectilinear motion of piston is converted into rotary by
(B) Slider crank
(C) Connecting rod
(D) Gudgeon pin

7. In an ideal machine, the output as compared to input is
(A) Less
(B) More
(C) Equal
(D) May be less or more depending on efficiency

8. In a mechanism, the fixed instantaneous centers are those centers which
(A) Remain in the same place for all configurations of the mechanism
(B) Vary with the configuration of the mechanism
(C) Moves as the mechanism moves, but joints are of permanent nature
(D) None of the above

9. At the nodal point in a shaft, the amplitude for torsional vibration will be
(A) Minimum
(B) Maximum
(C) Zero
(D) Infinity

10. In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
(A) Less sensitive
(B) More sensitive
(C) Unaffected of sensitivity
(D) Isochronous

11. The two elements of a pair are said to form a higher pair, when they
(A) Have a surface contact when in motion
(B) Have a line or point contact when in motion
(C) Are kept in contact by the action of external forces, when in motion
(D) Permit relative motion

12. Torsional vibrations are said to occur when the particles of a body moves
(A) Perpendicular to its axis
(B) Parallel to its axis
(C) In a circle about its axis
(D) None of these

13. A point on a link connecting double slider crank chain traces a
(A) Ellipse
(B) Circle
(C) Parabola
(D) Hyperbola

14. In a mechanism, usually one link is fixed. If the fixed link is changed in a kinematic chain, then relative motion of other links
(A) Will remain same
(B) Will change
(C) Could change or remain unaltered depending on which link is fixed
(D) Will not occur

15. Two heavy rotating masses are connected by shafts of lengths l₁, l₂ and l₃ and the corresponding diameters are d₁, d₂ and d₃. This system is reduced to a torsionally equivalent system having uniform diameter d = d₁ of the shaft. The equivalent length of the shaft is
(A) (l₁ + l₂ + l₃)/3
(B) l = l₁ + l₂.(d₁/d₂)³ + l₂.(d₁/d₃)³
(C) l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴
(D) l₁ + l₂ + l₃

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