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

1. 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

2. The critical speed of a shaft in revolution per second is __________ as that of natural frequency of transverse vibration.
A. Same
B. Different
C. Unpredictable
D. None of these
Answer : A

3. 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

4. The two elements of a pair are said to form a _________ when they permit relative motion between them.
A. Open pair
B. Kinematic pair
C. Sliding pair
D. None of these
Answer : B

5. In a differential band brake as shown in the below figure, if the length OB is greater than OA, then the force P at C should act in the downward direction.
A. Yes
B. No
C. Unpredictable
D. None of these
Answer : B

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
Answer : A

7. If two moving elements have surface contact in motion, such pair is known as
A. Sliding pair
B. Rolling pair
C. Surface pair
D. Higher pair
Answer : D

8. A universal joint is an example of
A. Higher pair
B. Lower pair
C. Rolling pair
D. Sliding pair
Answer : B

9. In gears, interference takes place when
A. The tip of a tooth of a mating gear digs into the portion between base and root circles
B. Gears do not move smoothly in the absence of lubrication
C. Pitch of the gears is not same
D. Gear teeth are undercut
Answer : A

10. The component of the acceleration, parallel to the velocity of the particle, at the given instant is called
A. Radial component
B. Tangential component
C. Coriolis component
D. None of these
Answer : B

11. In railway axle boxes, the bearing used is
A. Deep groove ball bearing
B. Double row self aligning ball bearing
C. Double row spherical roller bearing
D. Cylindrical roller bearing
Answer : C

12. The equation of motion for a single degree of freedom system with viscous damping is 4(dx²/dt²) + 9(dx/dt) + 16x. The damping ratio of the system is
A. 9/8
B. 9/82
C. 9/16
D. 9/128
Answer : C

13. In S.H.M., the velocity vector w.r.t. displacement vector
A. Leads by 90°
B. Lags by 90°
C. Leads by 180°
D. Are in phase
Answer : A

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

15. The frictional torque transmitted in a flat pivot bearing with assumption of uniform pressure is _________ as compared to uniform wear.
A. Less
B. More
C. Same
D. None of these
Answer : B

16. The centre of percussion is below the centre of gravity of the body and is at a distance equal to
A. h/k_G
B. h²/k_G
C. k_G²/h
D. h × k_G
Answer : C

17. Throw of a cam is the maximum distance of the follower from
A. Base circle
B. Pitch circle
C. Root circle
D. Prime circle
Answer : A

18. 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
Answer : D

19. A slider crank chain consists of following numbers of turning and sliding pairs
A. 1, 3
B. 2, 2
C. 3, 1
D. 4, 0
Answer : C

20. The purpose of a link is to
A. Transmit motion
B. Guide other links
C. Act as a support
D. All of the above
Answer : D

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

22. The acceleration of the particle moving with simple harmonic motion is _________ at the mean position.
A. Zero
B. Minimum
C. Maximum
D. None of these
Answer : A

23. The mechanism consisting of three turning pairs and one sliding pair, is called a
A. Single slider crank chain
B. Whitworth quick return motion mechanism
C. Crank and slotted lever quick return motion mechanism
D. All of the above
Answer : D

24. The amplitude of vibration is always __________ the radius of the circle.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A

25. In a coupling rod of a locomotive, each of the four pairs is a ________ pair.
A. Sliding
B. Turning
C. Rolling
D. Screw
Answer : B

26. The power from the engine to the rear axle of an automobile is transmitted by means of
A. Worm and worm wheel
B. Spur gears
C. Bevel gears
D. Hooke's joint
Answer : D

27. A system of masses rotating in different parallel planes is in dynamic balance if the
A. Resultant force is equal to zero
B. Resultant couple is equal to zero
C. Resultant force and resultant couple are both equal to zero
D. Resultant force is numerically equal to the resultant couple, but neither of them need necessarily be zero
Answer : C

28. In a hydrodynamic journal bearing, there is
A. A very thin film of lubricant between the journal and the bearing such that there is contact between the journal and the bearing
B. A thick film of lubricant between the journal and the bearing
C. No lubricant between the journal and the bearing
D. A forced lubricant between the journal and the bearing
Answer : B

29. The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be
A. To dip the nose and tail
B. To raise the nose and tail
C. To raise the nose and dip the tail
D. To dip the nose and raise the tail
Answer : C

30. In order to double the period of a simple pendulum, the length of the string should be
A. Halved
B. Doubled
C. Quadrupled
D. None of these
Answer : C

31. The Klein's diagram is useful to find
A. Displacement of various parts
B. Velocity of various parts
C. Acceleration of various parts
D. Angular acceleration of various parts
Answer : C

32. When the crank is at the outer dead centre, in a reciprocating steam engine, then the acceleration of the piston will be
A. ?² r {(n + 1)/n}
B. ?² r {(n - 1)/n}
C. ?² r {n/(n + 1)}
D. ?² r {n/(n - 1)}
Answer : B

33. In a screw jack, the effort required to lower the load W is given by
A. P = W tan(? - ?)
B. P = W tan(? + ?)
C. P = W tan(? - ?)
D. P = W cos(? + ?)
Answer : C

34. A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the
A. Magnitude of the forces on journal
B. Angular velocity of journal
C. Clearance between journal and bearing
D. Radius of journal
Answer : D

35. In a radial cam, the follower moves
A. In a direction perpendicular to the cam axis
B. In a direction parallel to the cam axis
C. In any direction irrespective of the cam axis
D. Along the cam axis
Answer : A

36. TJIE horse power transmitted by a belt is dependent upon
A. Tension on tight side of belt
B. Tension on slack side of belt
C. Radius of pulley
D. All of the above
Answer : D

37. The product of the diametral pitch and circular pitch is equal to
A. 1
B. 1/?
C. ?
D. 2 ?
Answer : C

38. Elements of pairs held together mechanically is known as
A. Closed pair
B. Open pair
C. Mechanical pair
D. Rolling pair
Answer : A

39. When the radius of rotation of balls __________ as the equilibrium speed increases, the governor is said to be unstable.
A. Remains constant
B. Decreases
C. Increases
D. None of these
Answer : B

40. Which of the following is an inversion of Single slider crank chain?
A. Beam engine
B. Rotary engine
C. Oldhams coupling
D. Elliptical trammel
Answer : B

41. The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as
A. Static friction
B. Dynamic friction
C. Limiting friction
D. Coefficient of friction
Answer : C

42. The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as
A. Damping factor
B. Damping coefficient
C. Logarithmic decrement
D. Magnification factor
Answer : D

43. The magnitude of linear velocity of a point B on a link AB relative to point A is (Where ? = Angular velocity of the link AB)
A. ? × AB
B. ? × (AB)²
C. ?² × AB
D. (? × AB²
Answer : A

44. The indicator using Watt mechanism is known as
A. Thompson indicator
B. Richard indicator
C. Simplex indicator
D. Thomson indicator
Answer : B

45. A cam with a roller follower would constitute following type of pair
A. Lower pair
B. Higher pair
C. Open pair
D. Close pair
Answer : B

46. The Scott-Russell mechanism consists of
A. Sliding and turning pairs
B. Sliding and rotary pairs
C. Turning and rotary pairs
D. Sliding pairs only
Answer : A

47. A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
A. a is +ve and b = 0
B. a = 0 and b is +ve
C. a is +ve and b is -ve
D. a is +ve and b is also +ve
Answer : A

48. Which of the following is a turning 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 : B

49. 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

50. In a steam engine, the distance by which the outer edge of the Dslide valve overlaps the steam port is called
A. Lead
B. Steam lap
C. Exhaust lap
D. None of these
Answer : B