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

1. The example of spherical pair is
A. Bolt and nut
B. Lead screw of a lathe
C. Ball and socket joint
D. Ball bearing and roller bearing
Answer : C

2. A Hartnell governor is a
A. Dead weight governor
B. Pendulum type governor
C. Spring loaded governor
D. Inertia governor
Answer : C

3. The velocity of a body moving with simple harmonic motion is __________ at the mean position.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : C

4. The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ?? rad/s in the clockwise direction and the link OB turns with angular velocity ?? rad/s in the clockwise direction, then the rubbing velocity at the pin joint O is (where r = Radius of the pin at O)
A. ??.??.r
B. (?? - ??)r
C. (?? + ??)r
D. (?? - ??)2r
Answer : B

5. In a drag link quick return mechanism, the shortest link is always fixed. The sum of the shortest and longest link is
A. Equal to sum of other two
B. Greater than sum of other two
C. Less than sum of other two
D. There is no such relationship
Answer : C

6. The D-slide valve is also known as
A. Inside admission valve
B. Outside admission valve
C. Piston slide valve
D. None of these
Answer : B

7. The velocity of sliding __________ the distance of the point of contact from the pitch point.
A. Is directly proportional to
B. Is inversely proportional to
C. Is equal to cos ? multiplied by
D. Does not depend upon
Answer : A

8. 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? = k_G
B. l? = k_G
C. l?l? = k_G
D. l?l? = k_G²
Answer : D

9. Which of the following is used to control the speed variations of the engine caused by the fluctuations of the engine turning moment?
A. D-slide valve
B. Governor
C. Flywheel
D. Meyer's expansion valve
Answer : C

10. When brakes are applied to all the four wheels of a moving car, the distance travelled by the car before it is brought to rest, will be
A. Maximum
B. Minimum
C. Zero
D. None of these
Answer : B

11. In a circular arc cam with roller follower, the acceleration in any position of the lift will depend only upon
A. Total lift, total angle of lift, minimum radius of cam and cam speed
B. Radius of circular arc, cam speed, location of centre of circular arc and roller diameter
C. Mass of cam follower linkage, spring stiffness and cam speed
D. Total lift, centre of gravity of the cam and cam speed
Answer : A

12. The centre of gravity of a coupler link in a four bar mechanism will experience
A. No acceleration
B. Only linear acceleration
C. Only angular acceleration
D. Both linear and angular acceleration
Answer : D

13. A higher pair has__________.
A. Point contact
B. Surface contact
C. No contact
D. None of the above
Answer : A

14. The total number of instantaneous centres for a mechanism consisting of n links are
A. n/2
B. n
C. n - 1
D. n(n - 1)/2
Answer : D

15. Whitworth quick return mechanism is obtained by inversion of
A. Slider crank mechanism
B. Kinematic chain
C. Five link mechanism
D. Roller cam mechanism
Answer : A

16. Which of the following is an example of sliding pair?
A. Piston and cylinder of a reciprocating steam engine
B. Shaft with collars at both ends fitted into a circular hole
C. Lead screw of a lathe with nut
D. Ball and a socket joint
Answer : A

17. A single degree of freedom system is given by, m × (d²x/dt²) + c × (dx/dt) + sx = F.cos?.t with usual notations. It represents
A. Free vibration with damping
B. Free vibration without damping
C. Forced vibration with damping
D. Forced vibration without damping
Answer : C

18. Kinematic 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 : D

19. In an open pair, the two elements of a pair
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. Are not held together mechanically
Answer : D

20. An exact straight line motion mechanism is a
A. Scott-Russell's mechanism
B. Hart's mechanism
C. Peaucellier's mechanism
D. All of these
Answer : D

21. 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
Answer : D

22. 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

23. When the axes of the first and last wheels are coaxial, then the train is known as
A. Simple train of wheels
B. Compound train of wheels
C. Reverted gear train
D. Epicyclic gear train
Answer : C

24. The danger of breakage and vibration is maximum
A. Below the critical speed
B. Near the critical speed
C. Above the critical speed
D. None of these
Answer : B

25. The contact ratio for gears is
A. Zero
B. Less than one
C. Greater than one
D. Infinity
Answer : C

26. The pitching of a ship produces forces on the bearings which act __________ to the motion of the ship.
A. Vertically and parallel
B. Vertically and perpendicular
C. Horizontally and parallel
D. Horizontally and perpendicular
Answer : D

27. 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

28. Two pulleys of radii r? and r? and at distance x apart are connected by means of an open belt drive. The length of the belt is
A. ? (r? + r?) + (r? + r?)²/x + 2x
B. ? (r? + r?) + (r? - r?)²/x + 2x
C. ? (r? - r?) + (r? - r?)²/x + 2x
D. ? (r? - r?) + (r? + r?)²/x + 2x
Answer : B

29. A typewriter mechanism has 7 numbers of binary joints, six links and none of higher pairs. The mechanism is
A. Kinematically sound
B. Not sound
C. Soundness would depend upon which link is kept fixed
D. Data is not sufficient to determine same
Answer : A

30. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform pressure, is
A. (1/2). ? W cosec? (r? + r?)
B. (2/3). ? W cosec? (r? + r?)
C. (1/2). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
D. (2/3). ? W cosec? [(r?³ - r?³)/(r?² - r?²)]
Answer : D

31. Which of the following is false statement in respect of differences between machine and structure?
A. Machines transmit mechanical work, whereas structures transmit forces
B. In machines, relative motion exists between its members, whereas same does not exist in case of structures
C. Machines modify movement and work, whereas structures modify forces
D. Efficiency of machines as well as structures is below 100%
Answer : D

32. The relation between the controlling force (Fc) and radius of rotation (r) for a stable spring controlled governor is
A. F_c = ar + b
B. F_c = ar - b
C. F_c = ar
D. F_c = a/r + b
Answer : B

33. ________ is an inversion of Double slider crank chain.
A. Coupling rod of a locomotive
B. Scotch yoke mechanism
C. Hand pump
D. Reciprocating engine
Answer : B

34. The lower pair is a
A. Open pair
B. Closed pair
C. Sliding pair
D. Point contact pair
Answer : B

35. The swaying couple is due to the
A. Primary unbalanced force
B. Secondary unbalanced force
C. Two cylinders of locomotive
D. Partial balancing
Answer : A

36. A circular bar moving in a round hole is an example of
A. Incompletely constrained motion
B. Partially constrained motion
C. Completely constrained motion
D. Successfully constrained motion
Answer : A

37. 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
Answer : C

38. In automobiles the power is transmitted from gear box to differential through
A. Bevel gear
B. Universal joint
C. Hooke's joint
D. Knuckle joint
Answer : C

39. The angle of inclination of the plane, at which the body begins to move down the plane is called
A. Angle of friction
B. Angle of repose
C. Angle of projection
D. None of these
Answer : B

40. The coriolis component of acceleration leads the sliding velocity by
A. 45°
B. 90°
C. 135°
D. 180°
Answer : B

41. The Bifilar suspension method is used to determine
A. Natural frequency of vibration
B. Position of balancing weights
C. Moment of inertia
D. Centripetal acceleration
Answer : C

42. The transmissibility, for all values of damping factor, will be less than unity, if ?/?_n is
A. Equal to 1
B. Less than 2
C. Equal to 2
D. Greater than 2
Answer : D

43. The acceleration of a particle moving with simple harmonic motion, at any instant is given by
A. ?x
B. ?²x
C. ?²/x
D. ?³/x
Answer : B

44. The following is the inversion of slider crank chain mechanism
A. Whitworth quick return mechanism
B. Hand pump
C. Oscillating cylinder engine
D. All of the above
Answer : D

45. 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

46. The pressure angle of a cam is the angle between the direction of the follower motion and a normal to the
A. Pitch circle
B. Base circle
C. Pitch curve
D. Prime circle
Answer : C

47. Rectilinear motion of piston is converted into rotary by
A. Cross head
B. Slider crank
C. Connecting rod
D. Gudgeon pin
Answer : B

48. With usual notations for different parameters involved, the maximum fluctuations of energy for a flywheel is given by
A. 2EC_S
B. EC_S/2
C. 2EC_S²
D. 2E²C_S
Answer : A

49. The fundamental equation for correct steering is (where ? and ? = Angle through which the axis of the outer wheel and inner wheel turns respectively, c = Distance between the pivots of the front axles, and d = Wheel base)
A. sin? + sin? = b/c
B. cos? - sin? = c/b
C. cot? - cot? = c/b
D. tan? + cot? = b/c
Answer : C

50. 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