1. Which of the following is incorrect regarding inertia force?
Correct : D. same direction as of accelerating force
2. Inertia torque acts in the same direction as the accelerating couple?
Correct : B. false
3. If a force has a line of action at a distance h from the centre of gravity, then the value of h is given by
Correct : A. i. α/f
4. D-Alembert’s principle is used for which of the following?
Correct : B. change dynamic problem to static problem
5. 2 D ALEMBERT'S PRINCIPLE - DYNAMIC ANALYSIS IN RECIPROCATING ENGINES
Correct : A. reversed effective force
6. A body remains in equilibrium if
Correct : B. inertia force is applied in the direction opposite to the resultant force
7. Inertia force and the reversed effective force are the same.
Correct : A. true
8. In the following picture the G is the center of gravity, the quantity h is known as the “offset”. I is the moment of inertia and k is the radius of gyration. Offset’s value is given by?
Correct : A. i.α/f
9. Considering a four bar chain with each link having linear and angular acceleration, applying D-Alembert’s principle will never result in which of the following member?
Correct : A. 2- force member
10. Piston effort acts along the line of stroke.
Correct : A. true
11. In a horizontal engine, reciprocating parts are accelerated when the piston moves from
Correct : A. tdc to bdc
12. In a horizontal engine, reciprocating parts are retarded when the piston moves from
Correct : B. bdc to tdc
13. When the piston is accelerated, the piston effort is given by which of the following the equation?
Correct : B. f(l) + f(i)
14. In the presence of frictional resistance, the expression for piston effort is
Correct : C. f(l) ± f(i) – r(f)
15. Crank effort is the product of crank pin radius and
Correct : B. crankpin effort
16. In a horizontal engine, the weight of the reciprocating parts also add/subtract to the piston effort.
Correct : B. false
17. For the given data of an Internal combustion engine : Mass of parts = 180 kg bore = 175 mm, length of stroke = 200 mm, engine speed = 500 r.p.m., length of connecting rod = 400 mm and crank angle = 60° from T.D.C, find the inertia force.
Correct : C. 18.53 n
18. 45 N/mm2. The connecting rod length between centres is 1.2 m and the cylinder bore is 0.5 m. If the engine runs at 250 r.p.m. and if the effect of piston rod diameter is neglected, calculate the net load on piston.
Correct : D. 88357 n
19. Multi cylinder engines are usually placed at an equal inclination to each other.
Correct : A. true
20. For a multicylinder engine, the coefficient of fluctuation of speed would vary with
Correct : B. remains unaffected
21. In the turning moment diagram of a multicylinder engine, the work done during exhaust stroke is by
Correct : B. on the gases
22. For a 4 cylinder engine, when the pressure inside the cylinders exceeds the atmospheric pressure then.
Correct : A. work is done by the gases
23. In a punching press, which of the following quantity is constant?
Correct : B. torque
24. In a punching press, load is 0 at the time of punching.
Correct : B. false
25. The maximum shear force required for punching depends on
Correct : A. sheared area
26. A machine punching 38 mm holes in 32 mm thick plate requires 7 N-m of energy per sq. mm of sheared area, find the maximum shear force required.
Correct : A. 26.7 kn
27. The relation between stroke punch s and radius of crank r is
Correct : B. s=2r
28. If the stroke punch is 100mm, find the radius of the crank in mm.
Correct : C. 50
29. Energy during actual punching operation is same as the energy supplied by the motor.
Correct : B. false
30. The balance energy required for punching is supplied by the flywheel by
Correct : B. decrease in its kinetic energy
31. When the length of the connecting rod is unknown then the value (θ2 –θ1)/2π is equal to
Correct : B. t/2s
32. The size of a cam depends upon
Correct : A. base circle
33. The angle between the direction of the follower motion and a normal to the pitch curve is called
Correct : D. pressure angle
34. The cam follower generally used in automobile engines is
Correct : C. spherical faced follower
35. The cam follower extensively used in air- craft engines is
Correct : D. roller follower
36. In a radial cam, the follower moves
Correct : A. in a direction perpendicular to the cam axis
37. A radial follower is one
Correct : A. that reciprocates in the guides
38. Ofset is provided to a cam follower mechanism to
Correct : A. minimise the side thrust
39. For low and moderate speed engines, the cam follower should move with
Correct : B. simple harmonic motion
40. For high speed engines, the cam follower should move with
Correct : D. cycloidal motion
41. Which of the following displacement diagrams should be chosen for better dynamic performance of a cam-follower mechanism ?
Correct : C. cycloidal motion
42. The displacement of a flat faced follower when it has contact with the flank of a circular arc cam, is given by
Correct : C. (r-r1)(1-cosθ)
43. The retardation of a flat faced follower when it has contact at the apex of the nose of a circular arc cam, is given by
Correct : A. ω2×oq
44. Centre of masses of the system lies on the axis of rotation.
Correct : D. 1, 3 and 4 only
45. Which of the following statements is correct about the balancing of a mechanical system?
Correct : C. both static as well as dynamic balance have to be achieved separately
46. In a locomotive, the ratio of the connecting rod length to the crank radius is kept very large in order to
Correct : B. minimize the effect of secondary forces
47. Multi-cylinder engines are desirable because
Correct : C. both (a) and (b)
48. Secondary forces in reciprocating mass on engine frame are
Correct : B. twice the frequency as of primary forces
49. Work produced by the 4-stroke engine is less because
Correct : A. one power stroke per 2 revolutions
50. When the work is done on the gases, which of the following effect is observed on the turning moment diagram?
Correct : A. formation of negative loop
51. Compression stroke results in
Correct : A. formation of negative loop
52. 4 strokes engine have a lower thermal efficiency than 2 stroke engine.
Correct : B. false
53. 3 BALANCING MACHINES-FIELD BALANCING OF DISCS AND ROTORS.
Correct : D. inertia forces
54. Balancing of single rotating mass by balancing masses in same plane and in different planes cannot take place.
Correct : B. false
55. Which of the following is true for centrifugal force causing unbalance?
Correct : A. direction changes with rotation
56. In a revolving rotor, the centrifugal force remains balanced as long as the centre of the mass of the rotor lies
Correct : B. on the axis of the shaft
57. If the unbalanced system is not set right then.
Correct : A. static forces develop
58. What is not the effect of unbalanced forces?
Correct : D. violation of conservation of mass principle
59. The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in
Correct : A. transverse vibrations
60. In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be
Correct : C. greater than unity
61. The accelerometer is used as a transducer to measure earthquake in Richter scale. Its design is based on the principle that
Correct : C. its natural frequency is equal to the frequency of vibration
62. Critical speed is expressed as
Correct : D. natural frequency of the shaft
63. The first critical speed of an automobile running on a sinusoidal road is calculated by (modeling it as a single degree of freedom system)
Correct : A. resonance
64. The natural frequency of a spring-mass system on earth is ωn. The natural frequency of this system on the moon (gmoon = gearth/6) is
Correct : A. ωn
65. 6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural frequency (fn), respectively, are
Correct : A. 0.471 and 1.19 hz
66. 5 m/s.
Correct : C. 3.49
67. Which of the following expression represent the angular acceleration α of the connecting rod?
Correct : A. −ω2 . sin θ/n
68. While calculating angular acceleration of the connecting rod, sin2(θ) term is neglected.
Correct : A. true
69. In a slider crank mechanism, the length of the crank and connecting rod are 180 mm and 540 mm respectively. The crank position is 45° from inner dead centre. The crank shaft speed is 450 r.p.m. (clockwise), calculate angular velocity of the connecting rod in rad/s.
Correct : B. 11.1
70. When a body is subjected to transverse vibrations, the stress induced in a body will be
Correct : B. bending stress
71. Longitudinal vibrations are said to occur when the particles of a body moves
Correct : B. parallel to its axis
72. When a body is subjected to transverse vibrations, the stress induced in a body will be
Correct : B. tensile stress
73. The factor which affects the critical speed of a shaft is
Correct : D. all of the mentioned
74. The ratio of the maximum displacement of the forced vibration to the deflection due to the static force, is known as
Correct : D. magnification factor
75. Which of the following systems produce a vibration in the foundation?
Correct : A. unbalanced machine
76. When a periodic disturbing force is applied to a machine, the force is transmitted to the foundation by the means of spring.
Correct : A. true
77. Which of the following is a type of transmitted force to the foundation?
Correct : A. damping force
78. If the damper is not provided and the system is in resonance, which of the following is the correct isolation factor?
Correct : D. infinity
79. If isolation factor is negative, then what is the phase difference between transmitted and disturbing force?
Correct : A. 180°
80. Which of the following is true regarding Ɛ>1?
Correct : A. transmitted force is greater than applied force
81. Isolation factor is twice the transmissibility ratio.
Correct : B. false
82. The height of a Watt’s governor is
Correct : D. inversely proportional to (speed)
83. A Watt’s governor can work satisfactorily at speeds from
Correct : C. 100 to 200 r.p.m
84. When the sleeve of a Porter governor moves downwards, the governor speed
Correct : B. decreases
85. In a Porter governor, the balls are attached to the extension of lower links.
Correct : A. true
86. A Hartnell governor is a
Correct : C. spring loaded governor
87. A Watt’s governor is a spring loaded governor.
Correct : B. false
88. Which of the following is a pendulum type governor?
Correct : A. watt’s governor
89. A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be
Correct : D. iωωp
90. 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
Correct : C. to raise the nose and dip of the tail
91. The steering of a ship means
Correct : B. turning of a complete ship in a curve towards right or left, while it moves forward
92. The rolling of a complete ship side-ways is known as pitching of a ship.
Correct : B. false
93. The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a right turn. The effect of gyroscopic couple acting on it will be to raise the stern and lower the bow.
Correct : A. true
94. The pitching of a ship is assumed to take place with simple harmonic motion.
Correct : A. true
95. Power is transmitted by an electric motor to a machine by using a belt drive. The tensions on the tight and slack side of the belt are 2200 N and 1000 N respectively and diameter of the pulley is 600 mm. If speed of the motor is 1500 r.p.m, find the power transmitted.
Correct : B. 56.548 kw
96. 6 x 10 = 6 rad/s.
Correct : A. 2.055 m
97. Calculate the work done per minute by a punch tool making 20 working strokes per min when a 30 mm diametre hole is punched in 5 mm thick plate with ultimate shear strength og 450 Mpa in each stroke.
Correct : A. 10.69 knm
98. In latitude 25.0 S, SA (spin axis) of a FG (free gyro) is in position S40E and horizontal. Find the tilt after 6 hours.
Correct : A. 61.16 up
99. The steering of a ship means
Correct : B. turning of a complete ship in a curve towards right r left, while it moves forward
100. When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be