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ESIC - Theory of Machines 1000+ MCQ [Solved] PDF Download

Thursday 9th of March 2023

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Downlaod Theory of Machines MCQ PDF
1. The Klein's method of construction for reciprocating engine mechanism
A. Is a simplified version of instantaneous centre method
B. Utilises a quadrilateral similar to the diagram of mechanism for reciprocating engine
C. Enables determination of coriolis component
D. Is based on the acceleration diagram
Answer : B
2. Which of the following statement is correct for involute gears?
A. The interference is inherently absent.
B. The variation in centre distance of shafts increases radial force.
C. A convex flank is always in contact with concave flank.
D. The pressure angle is constant throughout the teeth engagement.
Answer : D
3. The steering of a ship means
A. Movement of a complete ship up and down in vertical plane about transverse axis
B. Turning of a complete ship in a curve towards right or left, while it moves forward
C. Rolling of a complete ship sideways
D. None of the above
Answer : B
4. Which of the following mechanism is obtained from lower pair?
A. Gyroscope
B. Pantograph
C. Valve and valve gears
D. All of the above
Answer : D
5. The velocity of the rubbing surface __________ with the distance from the axis of the bearing.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : A
6. The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft, and I = Mass moment of inertia of the disc attached at the end of a shaft)
A. 2?. ?(q/I)
B. 2? qI
C. (1/2?). ?(q/I)
D. 1/2?
Answer : C
7. In a turning moment diagram, the variations of energy above and below the mean resisting torque line is called
A. Fluctuation of energy
B. Maximum fluctuation of energy
C. Coefficient of fluctuation of energy
D. None of these
Answer : A
8. A body is said to be under forced vibrations, when
A. There is a reduction in amplitude after every cycle of vibration
B. No external force acts on a body, after giving it an initial displacement
C. A body vibrates under the influence of external force
D. None of the above
Answer : A
9. To connect two parallel and coplanar shafts the following type of gearing is used
A. Spur gear
B. Bevel gear
C. Spiral gear
D. None of the above
Answer : A
10. The equivalent length of a simple pendulum which gives the same frequency as a compound pendulum is
A. h/(kG² + h²)
B. (kG² + h²)/h
C. h²/(kG² + h²)
D. (kG² + h²)/h²
Answer : B
11. Longitudinal 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
Answer : B
12. The essential condition of placing the two masses, so that the system becomes dynamically equivalent, is (where l? and l? = Distance of two masses from the centre of gravity of the body, and kG = Radius of gyration of the body)
A. l? = kG
B. l? = kG
C. l?l? = kG
D. l?l? = kG²
Answer : D
13. Which of the following statement is wrong?
A. A round bar in a round hole form a turning pair
B. A square bar in a square hole form a sliding pair
C. A vertical shaft in a foot step bearing forms a successful constraint
D. All of the above
Answer : C
14. 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
Answer : B
15. The frictional torque transmitted by a disc or plate clutch is same as that of
A. Flat pivot bearing
B. Flat collar bearing
C. Conical pivot bearing
D. Truncated conical pivot bearing
Answer : B
16. When a rigid body is suspended vertically and it oscillates with a small amplitude under the action of the force of gravity, the body is known as
A. Simple pendulum
B. Compound pendulum
C. Torsional pendulum
D. Second's pendulum
Answer : B
17. Kinematic pairs are those which have
A. Two elements held together mechanically
B. Two elements having relative motion
C. Two elements having Coriolis component
D. Minimum of two instantaneous centres
Answer : B
18. In a spring controlled governor, when the controlling force ________ as the radius of rotation increases, it is said to be a stable governor.
A. Remains constant
B. Decreases
C. Increases
D. None of these
Answer : C
19. The coriolis component of acceleration is taken into account for
A. Slider crank mechanism
B. Four bar chain mechanism
C. Quick return motion mechanism
D. All of these
Answer : C
20. Oldhams coupling is an inversion of the kinematic chain used in
A. Whitworth quick return mechanism
B. Elliptical trammels
C. Rotary engine
D. Universal joint
Answer : B
21. A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is
A. 2
B. 4
C. 3
D. None of the above
Answer : B
22. The contact ratio is given by
A. (Length of the path of approach)/(Circular pitch)
B. (Length of path of recess)/(Circular pitch)
C. (Length of the arc of contact)/(Circular pitch)
D. (Length of the arc of approach)/cos?
Answer : C
23. 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
Answer : B
24. It is required to connect two parallel shafts, the distance between whose axes is small and variable. The shafts are coupled by
A. Universal joint
B. Knuckle joint
C. Oldham's coupling
D. Flexible coupling
Answer : C
25. Cam size depends upon
A. Base circle
B. Pitch circle
C. Prime circle
D. Outer circle
Answer : A
26. Which of the following is a lower pair?
A. Ball and socket i
B. Piston and cylinder
C. Cam and follower
D. Both (A) and (B) above
Answer : D
27. Governor is used in automobile to
A. Decrease the variation of speed
B. Maximize the fuel economy
C. Limit the vehicle speed
D. Maintain constant engine speed
Answer : C
28. A motor car moving at a certain speed takes a left turn in a curved path. If the engine rotates in the same direction as that of wheels, men due to centrifugal forc
A. The reaction on me inner wheels increases and on the outer wheels decreases
B. The reaction on the outer wheels increases and on the inner wheels decreases
C. The reaction on the front wheels increases and on the rear wheels decreases
D. The reaction on the rear wheels increases and on the front wheels decreases
Answer : B
29. The sense of coriolis component 2 ?v is same as that of the relative velocity vector v rotated at
A. 45° in the direction of rotation of the link containing the path
B. 45° in the direction opposite to the rotation of the link containing the path
C. 90° in the direction of rotation of the link containing the path
D. 180° in the direction opposite to the rotation of the link containing the path
Answer : C
30. Which of the following statements regarding laws governing the friction between dry surfaces are correct?
A. The friction force is dependent on the materials of the contact surfaces.
B. The friction force is directly proportional to the normal force.
C. The friction force is independent of me area of contact.
D. All of the above
Answer : D
31. In a cone pulley, if the sum of radii of the pulleys on the driving and driven shafts is Constant, then
A. Open belt drive is recommended
B. Crossed belt drive is recommended
C. Both open belt drive and crossed belt drive is recommended
D. The drive is recommended depending upon the torque transmitted
Answer : B
32. Instantaneous center of rotation of a link in a four bar mechanism lies on
A. Right side pivot of this link
B. Left side pivot of this link
C. A point obtained by intersection on extending adjoining links
D. Cant occur
Answer : C
33. The motion between a pair which takes place in __________ is known as incompletely constrained motion.
A. One direction only
B. Two directions only
C. More than one direction
D. None of these
Answer : C
34. The periodic time of one oscillation for a simple pendulum is
A. 2?. ?(g/l)
B. (1/2?). ?(g/l)
C. 2?. ?(l/g)
D. (1/2?). ?(l/g)
Answer : C
35. The velocity of the belt for maximum power is (where m = Mass of the belt in kg per metre length)
A. T/3
B. (T.g)/3
C. ?(T/3m)
D. ?(3m/T)
Answer : C
36. In a Hartnell governor, the compression of the spring is __________ the lift of the sleeve.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A
37. Ackermann steering gear consists of
A. Sliding pairs
B. Turning pairs
C. Rolling pairs
D. Higher pairs
Answer : B
38. In a shaper mechanism, the Coriolis component of acceleration will
A. Not exist
B. Exist
C. Depend on position of crank
D. None of the above
Answer : B
39. The rotating shafts tend to vibrate violently at whirling speeds because
A. The system is unbalanced
B. Bearing centre line coincides with the axis
C. The shafts are rotating at very high speeds
D. Resonance is caused due to the heavy mass of the rotor
Answer : D /div>
40. Two systems shall be dynamically equivalent when
A. The mass of two are same
B. C.G. of two coincides
C. M.I. of two about an axis through e.g. is equal
D. All of the above
Answer : D
41. The frictional torque transmitted in a conical pivot bearing, considering uniform pressure, is (where R = Radius of shaft, and ? = Semi-angle of the cone)
A. (1/2) ? W R cosec?
B. (2/3) ? W R cosec?
C. (3/4) ? W R cosec?
D. ? W R cosec?
Answer : B
42. The secondary unbalanced force due to inertia of reciprocating parts in a reciprocating engine is given by (where m = Mass of reciprocating parts, ? = Angular speed of crank, r = Radius of crank, ? = Angle of inclination of crank with the line of stroke, and n = Ratio of the length of connecting rod to radius of crank)
A. m.?².r sin?
B. m.?².r cos?
C. m.?².r (sin 2?/n)
D. m.?².r (cos 2?/n)
Answer : D
43. The length of a simple pendulum which gives the same frequency as the compound pendulum, is
A. kG + l?
B. kG² + l?
C. (kG² + l?²)/ l?
D. (kG + l?²)/ l?
Answer : C
44. In the below figure, PC is the connecting rod and OC is the crank making an angle ? with the line of stroke PO and rotates with uniform angular velocity at ? rad/s. The Klien's acceleration diagram for determining the acceleration of the piston P is shown by quadrilateral CQNO, the acceleration of the piston is _________ when the crank OC and connecting rod PC are at right angles to each other.
A. Infinity
B. Zero
C. Any +ve value
D. Any -ve value
Answer : B
45. For two governors A and B, the lift of sleeve of governor A is more than that of governor B, for a given fractional change in speed. It indicates that
A. Governor A is more sensitive than governor B
B. Governor B is more sensitive than governor A
C. Both governors A and B are equally sensitive
D. None of the above
Answer : A
46. When two links are connected by a pin joint, their instantaneous centre lies
A. On their point of contact
B. At the centre of curvature
C. At the centre of circle
D. At the pin joint
Answer : D
47. The direction of linear velocity of any point on a link with respect to another point on the same link is
A. Parallel to the link joining the points
B. Perpendicular to the link joining the points
C. At 45° to the link joining the points
D. None of the above
Answer : B
48. The maximum efficiency of spiral gears is (where ? = Shaft angle, and ? = Friction angle)
A. sin (? + ?) + 1/ cos (? - ?) + 1
B. cos (? - ?) + 1/ sin (? + ?) + 1
C. cos (? + ?) + 1/ cos (? - ?) + 1
D. cos (? - ?) + 1/ cos (? + ?) + 1
Answer : C
49. A circle passing through the pitch point with its center at the center of cam axis is known as
A. Pitch circle
B. Base circle
C. Prime circle
D. Outer circle
Answer : C
50. A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a
A. Structure
B. Mechanism
C. Kinematic chain
D. Inversion
Answer : C
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