1000+ Theory of Machines Multiple Choice Question Answer [Solved]

1. For a twin cylinder V-engine, the crank positions for primary reverse cranks and secondary direct cranks are shown in the below figure. The engine is a
A. 30° V-engine
B. 60° V-engine
C. 120° V-engine
D. 150° V-engine
Answer : A

2. In a reciprocating steam engine, when the crank has turned from inner dead centre through an angle ?, the angular velocity of the connecting rod is given by
A. ? sin?/(n² - sin²?)^1/2
B. ? cos?/(n² - cos²?)^1/2
C. ? sin?/(n² - cos²?)^1/2
D. ? cos?/(n² - sin²?)^1/2
Answer : D

3. When a body is subjected to transverse vibrations, the stress induced in a body will be
A. Shear stress
B. Bending stress
C. Tensile stress
D. Compressive stress
Answer : B

4. A governor is said to be stable, if the
A. Radius of rotation of balls increases as the equilibrium speed decreases
B. Radius of rotation of balls decreases as the equilibrium speed decreases
C. Radius of rotation of balls increases as the equilibrium speed increases
D. Radius of rotation of balls decreases as the equilibrium speed increases
Answer : C

5. When two pulleys of different diameters are connected by means of an open belt, the angle of contact at the ________ pulley must be taken into consideration.
A. Smaller
B. Larger
C. Either A or B
D. None of these
Answer : A

6. 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

7. In a reciprocating steam engine, which of the following forms a kinematic link?
A. Cylinder and piston
B. Piston rod and connecting rod
C. Crankshaft and flywheel
D. Flywheel and engine frame
Answer : C

8. The radial distance from the top of a tooth to the bottom of a tooth in a meshing gear, is called
A. Dedendum
B. Addendum
C. Clearance
D. Working depth
Answer : C

9. The maximum fluctuation of energy is the
A. Difference between the maximum and minimum energies
B. Sum of the maximum and minimum energies
C. Variations of energy above and below the mean resisting torque line
D. Ratio of the mean resisting torque to the workdone per cycle
Answer : A

10. In a locomotive, the resultant unbalanced force due to the two cylinders along the line of stroke, is known as
A. Tractive force
B. Swaying couple
C. Hammer blow
D. None of these
Answer : A

11. In Meyer's expansion valve, the expansion valve is driven by an eccentric having an angle of advance from
A. 50°-60°
B. 60°-70°
C. 70°-80°
D. 80°-90°
Answer : D

12. When a mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, then it will
A. Return to equilibrium position without oscillation
B. Oscillate with increasing time period
C. Oscillate with decreasing amplitude
D. Oscillate with constant amplitude
Answer : B

13. In a Hartnell governor, the lift of the sleeve is given by (where r? and r? = Max. and min. radii of rotation, x = Length of ball arm of the lever, and y = Length of sleeve arm of the lever)
A. (r? + r?) (y/x)
B. (r? + r?) (x/y)
C. (r? - r?) (y/x)
D. (r? - r?) (x/y)
Answer : C

14. 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
Answer : C

15. The relation between number of links (l) and number of joints (j) in a kinematic chain is
A. l = (1/2).(j + 2)
B. l = (2/3).(j + 2)
C. l = (3/4).(j + 3)
D. l = j + 4
Answer : B

16. Which of the following disciplines provides study of the relative motion between the parts of a machine and the forces acting on the parts?
A. Theory of machines
B. Applied mechanics
C. Mechanisms
D. Kinetics
Answer : A

17. 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

18. The face of the tooth is the
A. Surface of the top of tooth
B. Surface of tooth above the pitch surface
C. Width of tooth below the pitch surface
D. Width of tooth measured along the pitch circle
Answer : B

19. A simple spring-mass vibrating system has a natural frequency of fn. If the spring stiffness is halved and the mass is doubled, then the natural frequency will become
A. f_n/2
B. 2 f_n
C. 4 f_n
D. 8 f_n
Answer : A

40. In a four stroke I.C. engine, the turning moment during the compression stroke is
A. Positive throughout
B. Negative throughout
C. Positive during major portion of the stroke
D. Negative during major portion of the stroke
Answer : B

41. When the belt is stationary, it is subjected to some tension known as initial tension. The value of this tension is equal to the
A. Tension in the tight side of the belt
B. Tension in the slack side of the belt
C. Sum of the tensions on the tight side and slack side of the belt
D. Average tension of the tight side and slack side of the belt
Answer : D

42. If ?/?_n is very high for a body vibrating under steady state vibrations, the phase angle for all values of damping factors, will tend to approach
A. 0°
B. 90°
C. 180°
D. 360°
Answer : C

43. 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

44. The height of a Watt's governor (in metres) is equal to (where N = Speed of the arm and ball about the spindle axis)
A. 8.95/N²
B. 89.5/N²
C. 895/N²
D. 8950/N²
Answer : C

45. 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

46. In a gear having involute teeth, the normal to the involute is a tangent to the
A. Pitch circle
B. Base circle
C. Addendum circle
D. Dedendum circle
Answer : B

47. The acceleration of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
A. ?² R cos?
B. ?² (R - r?) cos?
C. ?² (R - r?) sin?
D. ?² r? sin?
Answer : B

48. According to Kennedy's theorem, if three bodies have plane motions, their instantaneous centers lie on
A. A triangle
B. A point
C. Two lines
D. A straight line
Answer : D

49. A chain comprises of 5 links having 5 joints. Is it kinematic chain?
A. Yes
B. No
C. It is a marginal case
D. Data are insufficient to determine it
Answer : B

50. The secondary unbalanced force is maximum __________ in one revolution of the crank.
A. Two times
B. Four times
C. Eight times
D. Sixteen times
Answer : B