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. Why the inertia torque acts in the opposite direction to the accelerating couple?
Correct : A. bring the body in equilibrium
7. A body remains in equilibrium if
Correct : B. inertia force is applied in the direction opposite to the resultant force
8. Inertia force and the reversed effective force are the same.
Correct : A. true
9. 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
10. 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
11. The net force acting on the crosshead pin is known as
Correct : C. piston effort
12. Piston effort acts along the line of stroke.
Correct : A. true
13. In a horizontal engine, reciprocating parts are accelerated when the piston moves from
Correct : A. tdc to bdc
14. In a horizontal engine, reciprocating parts are retarded when the piston moves from
Correct : B. bdc to tdc
15. When the piston is accelerated, the piston effort is given by which of the following the equation?
Correct : B. f(l) + f(i)
16. In the presence of frictional resistance, the expression for piston effort is
Correct : C. f(l) ± f(i) – r(f)
17. Crank effort is the product of crank pin radius and
Correct : B. crankpin effort
18. In a horizontal engine, the weight of the reciprocating parts also add/subtract to the piston effort.
Correct : B. false
19. 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
20. 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
21. 2 m and the cylinder bore is 0.5 m. engine runs at 250 r.p.m & 30° from T.D.C. Find the piston effort.
Correct : C. 37.3 kn
22. Multi cylinder engines are usually placed at an equal inclination to each other.
Correct : A. true
23. For a multicylinder engine, the coefficient of fluctuation of speed would vary with
Correct : B. remains unaffected
24. For a 4 cylinder engine, if the minimum speed of the engine is half the maximum speed, then coefficient of fluctuation is
Correct : D. 0.66
25. In the turning moment diagram of a multicylinder engine, the work done during exhaust stroke is by
Correct : B. on the gases
26. For a 4 cylinder engine, when the pressure inside the cylinders exceeds the atmospheric pressure then.
Correct : A. work is done by the gases
27. In a punching press, which of the following quantity is constant?
Correct : B. torque
28. In a punching press, load is 0 at the time of punching.
Correct : B. false
29. The maximum shear force required for punching depends on
Correct : A. sheared area
30. 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
31. The relation between stroke punch s and radius of crank r is
Correct : B. s=2r
32. If the stroke punch is 100mm, find the radius of the crank in mm.
Correct : C. 50
33. Energy during actual punching operation is same as the energy supplied by the motor.
Correct : B. false
34. The balance energy required for punching is supplied by the flywheel by
Correct : B. decrease in its kinetic energy
35. When the length of the connecting rod is unknown then the value (θ2 –θ1)/2π is equal to
Correct : B. t/2s
36. The size of a cam depends upon
Correct : A. base circle
37. The angle between the direction of the follower motion and a normal to the pitch curve is called
Correct : D. pressure angle
38. A circle drawn with centre as the cam centre and radius equal to the distance between the cam centre and the point on the pitch curve at which the pressure angle is maximum, is called
Correct : B. pitch circle
39. The cam follower generally used in automobile engines is
Correct : C. spherical faced follower
40. The cam follower extensively used in air- craft engines is
Correct : D. roller follower
41. In a radial cam, the follower moves
Correct : A. in a direction perpendicular to the cam axis
42. A radial follower is one
Correct : A. that reciprocates in the guides
43. Ofset is provided to a cam follower mechanism to
Correct : A. minimise the side thrust
44. For low and moderate speed engines, the cam follower should move with
Correct : B. simple harmonic motion
45. For high speed engines, the cam follower should move with
Correct : D. cycloidal motion
46. Which of the following displacement diagrams should be chosen for better dynamic performance of a cam-follower mechanism ?
Correct : C. cycloidal motion
47. The linear velocity of the reciprocating roller follower when it has contact with the straight flanks of the tangent cam, is given by
Correct : C. ωr1+r2)sinθsec2θ
48. 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)
49. 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
50. Centre of masses of the system lies on the axis of rotation.
Correct : D. 1, 3 and 4 only
51. 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
52. 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
53. In case of partial balancing of locomotives, the maximum magnitude of the unbalanced force perpendicular to the line of stroke is called hammer blow and this has to be limited by proper choice of the balancing mass and its radial position.
Correct : A. true
54. Multi-cylinder engines are desirable because
Correct : C. both (a) and (b)
55. Secondary forces in reciprocating mass on engine frame are
Correct : B. twice the frequency as of primary forces
56. Which of the following process is not the part of working of a 4 stroke I.C Engine?
Correct : D. turbine flow
57. 4-stroke engine has one power stroke per 2 revolutions hence turning moment diagram is uniform.
Correct : B. false
58. Work produced by the 4-stroke engine is less because
Correct : A. one power stroke per 2 revolutions
59. A negative loop is formed in the turning moment diagram because the pressure inside the cylinder is than the atmospheric pressure.
Correct : C. less
60. When the work is by on the gases, which of the following effect is observed on the turning moment diagram?
Correct : B. formation of positive loop
61. Compression stroke results in
Correct : A. formation of negative loop
62. 4 strokes engine have a lower thermal efficiency than 2 stroke engine.
Correct : B. false
63. While drawing the turning moment diagram, which of the forces in not taken into account?
Correct : D. coriolis force
64. In the given turning moment diagram, the process X is known as
Correct : C. power
65. 3 BALANCING MACHINES-FIELD BALANCING OF DISCS AND ROTORS.
Correct : D. inertia forces
66. Balancing of single rotating mass by balancing masses in same plane and in different planes cannot take place.
Correct : B. false
67. Which of the following is true for centrifugal force causing unbalance?
Correct : A. direction changes with rotation
68. 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
69. If the unbalanced system is not set right then.
Correct : A. static forces develop
70. What is not the effect of unbalanced forces?
Correct : D. violation of conservation of mass principle
71. What is the effect of a rotating mass of a shaft on a system?
Correct : A. bend the shaft
72. Balancing of reciprocating masses is the process of providing the second mass in order to counteract the effect of the centrifugal force of the first mass.
Correct : B. false
73. 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
74. When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
Correct : C. damped vibration
75. In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be
Correct : C. greater than unity
76. 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
77. Critical speed is expressed as
Correct : D. natural frequency of the shaft
78. 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
79. 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
80. A vehicle suspension system consists of a spring and a damper. The stiffness of the spring is 3.6 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
81. If the crank and the connecting rod are 300 mm and 1 m long respectively and the crank rotates at a constant speed of 250 r.p.m., determine the crank angle at which the maximum velocity occurs is
Correct : B. 75
82. 5 m/s.
Correct : C. 3.49
83. Which of the following expression represent the angular acceleration α of the connecting rod?
Correct : A. −ω2 . sin θ/n
84. While calculating angular acceleration of the connecting rod, sin2(θ) term is neglected.
Correct : A. true
85. 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
86. When a body is subjected to transverse vibrations, the stress induced in a body will be
Correct : B. bending stress
87. 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
88. For an under damped harmonic oscillator, resonance
Correct : C. occurs when excitation frequency is equal to undamped natural frequency
89. When there is a reduction in amplitude over every cycle of vibration, then the body is said to have
Correct : C. damped vibration
90. Longitudinal vibrations are said to occur when the particles of a body moves
Correct : B. parallel to its axis
91. When a body is subjected to transverse vibrations, the stress induced in a body will be
Correct : B. tensile stress
92. The natural frequency (in Hz) of free longitudinal vibrations is equal to
Correct : D. all of the mentioned
93. The factor which affects the critical speed of a shaft is
Correct : D. all of the mentioned
94. In under damped vibrating system, if x1 and x2 are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to
Correct : B. log (x1/x2)
95. 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
96. Which of the following systems produce a vibration in the foundation?
Correct : A. unbalanced machine
97. 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
98. Which of the following is correct regarding isolation factor?
Correct : A. dimensionless quantity
99. Which of the following is a type of transmitted force to the foundation?
Correct : A. damping force
100. If isolation factor is negative, then what is the phase difference between transmitted and disturbing force?