Theory of Machines 1000+ MCQ with answer for IBPS PO

1. For fluctuating loads, well suited bearing is
A. Ball bearing
B. Roller bearing
C. Needle roller bearing
D. Thrust bearing
Answer : C

2. 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

3. The minimum force required to slide a body of weight W on a rough horizontal plane is
A. W sin?
B. W cos?
C. W tan?
D. W cosec?
Answer : A

4. 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

5. 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

6. 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

7. 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
Answer : A

8. The instantaneous centres which vary with the configuration of mechanism are called
A. Permanent instantaneous centres
B. Fixed instantaneous centres
C. Neither fixed nor permanent instantaneous centres
D. None of the above
Answer : C

9. In order to balance the reciprocating masses,
A. Primary forces and couples must be balanced
B. Secondary forces and couples must be balanced
C. Both (A) and (B)
D. None of these
Answer : C

10. A spring controlled governor is said to be unstable when the controlling force
A. Increases as the radius of rotation decreases
B. Increases as the radius of rotation increases
C. Decreases as the radius of rotation increases
D. Remains constant for all radii of rotation
Answer : C

11. The sensitiveness of the governor __________ as the speed range decreases.
A. Remains unaffected
B. Decreases
C. Increases
D. None of these
Answer : C

12. 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

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

14. Transmission angle is the angle between
A. Input link and coupler
B. Input link and fixed link
C. Output link and coupler
D. Output link and fixed link
Answer : C

15. 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

16. 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

17. If the radius of gyration of a compound pendulum about an axis through e.g. is more, then its frequency of oscillation will be
A. Less
B. More
C. Same
D. Data are insufficient to determine same
Answer : A

18. Which of the following statement is correct?
A. The power absorbed in operating the piston valve is less than D-slide valve
B. The wear of the piston valve is less than the wear of the D-slide valve
C. The D-slide valve is also called outside admission valve.
D. All of the above
Answer : D

19. The frictional torque transmitted in a truncated conical pivot bearing, considering uniform wear, 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 : A

20. When the particles of a body moves perpendicular to its axis, then the body is said to have
A. Longitudinal vibration
B. Transverse vibration
C. Torsional vibration
D. None of these
Answer : B

21. 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

22. The tractive force is maximum or minimum when the angle of inclination of crank with the line of stroke (?) is equal to
A. 0° and 90°
B. 90° and 180°
C. 135° and 315°
D. 270° and 360°
Answer : B

23. If the damping factor for a vibrating system is unity, then the system will be
A. Over damped
B. Under damped
C. Critically damped
D. Without vibrations
Answer : C

24. A flywheel is fitted to the crankshaft of an engine having W as the amount of indicated work per revolution and permissible limits of coefficient of fluctuation of energy and speed as CE and CS respectively. The kinetic energy of the flywheel is given by
A. 2 W C_E / C_S
B. W C_E / 2C_S
C. W C_E / C_S
D. W C_S / 2C_E
Answer : B

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

26. 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. 3
C. 4
D. 5
Answer : C

27. The factional torque for square thread at the mean radius r while raising load W is given by
A. T = W.r tan(? - ?)
B. T = W.r tan(? + ?)
C. T = W.r tan?
D. T = W.r tan?
Answer : B

28. A rotor supported at A and B carries two masses as shown in the below figure. The rotor is
A. Dynamically balanced
B. Statically balanced
C. Statically and dynamically balanced
D. Not balanced
Answer : C

29. In a screw jack, the effort required to lift the load W is given by (where ? = Helix angle, and ? = Angle of friction)
A. P = W tan(? - ?)
B. P = W tan(? + ?)
C. P = W tan(? - ?)
D. P = W cos(? + ?)
Answer : B

30. The equation of free vibrations of a system is (d²x/dt²) +36 ?²x, its natural frequency is
A. 3 Hz
B. 3? Hz
C. 6 Hz
D. 6? Hz
Answer : A

31. The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the
A. Unbalanced couples are caused only at higher speeds
B. Unbalanced forces are not dangerous at higher speeds
C. Effects of unbalances are proportional to the square of the speed
D. Effects of unbalances are directly proportional to the speed
Answer : C

32. 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

33. The train value of a gear train is
A. Equal to velocity ratio of a gear train
B. Reciprocal of velocity ratio of a gear train
C. Always greater than unity
D. Always less than unity
Answer : B

34. When a point at the end of a link moves with constant angular velocity, its acceleration will have
A. Radial component only
B. Tangential component only
C. Coriolis component only
D. Radial and tangential components both
Answer : A

35. The equation of motion for a vibrating system with viscous damping is (d²x/dt²) + (c/m). (dx/dt) + (s/m). x = 0 If the roots of this equation are real, then the system will be
A. Over-damped
B. Under damped
C. Critically damped
D. Without vibrations
Answer : A

36. 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

37. The unbalanced force due to reciprocating masses
A. Varies in magnitude but constant in direction
B. Varies in direction but constant in magnitude
C. Varies in magnitude and direction both
D. Constant in magnitude and direction both
Answer : A

38. For low and moderate speed engines, the cam follower should move with
A. Uniform velocity
B. Simple harmonic motion
C. Uniform acceleration and retardation
D. Cycloidal motion
Answer : B

39. The example of completely constrained motion is a
A. Motion of a piston in the cylinder of a steam engine
B. Motion of a square bar in a square hole
C. Motion of a shaft with collars at each end in a circular hole
D. All of the above
Answer : D

40. For an isochronous Hartnell governor (where r? and r? = Maximum and minimum radius of rotation of balls respectively, S? and S? = Maximum and minimum force exerted on the sleeve respectively, and M = Mass on the sleeve)
A. (m.g + S?)/(m.g + S?) = r?/r?
B. (m.g - S?)/(m.g - S?) = r?/r?
C. S?/S? = r?/r?
D. S?/S? = r?/r?
Answer : A