McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 51. |
Compression stroke results in |
| A. | formation of negative loop |
| B. | formation of positive loop |
| C. | formation of an infinite loop |
| D. | formation of no loop |
| Answer» A. formation of negative loop | |
| 52. |
4 strokes engine have a lower thermal efficiency than 2 stroke engine. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 53. |
3 BALANCING MACHINES-FIELD BALANCING OF DISCS AND ROTORS. |
| A. | centripetal forces |
| B. | centrifugal forces |
| C. | friction forces |
| D. | inertia forces |
| Answer» D. inertia forces | |
| 54. |
Balancing of single rotating mass by balancing masses in same plane and in different planes cannot take place. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 55. |
Which of the following is true for centrifugal force causing unbalance? |
| A. | direction changes with rotation |
| B. | magnitude changes with rotation |
| C. | direction and magnitude both change with rotation |
| D. | direction and magnitude both remain unchanged with rotation |
| Answer» 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 |
| A. | below the axis of shaft |
| B. | on the axis of the shaft |
| C. | above the axis of shaft |
| D. | away from the axis of shaft |
| Answer» B. on the axis of the shaft | |
| 57. |
If the unbalanced system is not set right then. |
| A. | static forces develop |
| B. | dynamic forces develop |
| C. | tangential forces develop |
| D. | radial forces develop |
| Answer» A. static forces develop | |
| 58. |
What is not the effect of unbalanced forces? |
| A. | load on bearings |
| B. | dangerous vibrations |
| C. | stresses in various members |
| D. | violation of conservation of mass principle |
| Answer» 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 |
| A. | transverse vibrations |
| B. | torsional vibrations |
| C. | longitudinal vibrations |
| D. | none of the mentioned |
| Answer» A. transverse vibrations | |
| 60. |
In vibration isolation system, if ω/ωn < 2, then for all values of damping factor, the transmissibility will be |
| A. | less than unity |
| B. | equal to unity |
| C. | greater than unity |
| D. | zero |
| Answer» 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 |
| A. | its natural frequency is very low in comparison to the frequency of vibration |
| B. | its natural frequency is very high in comparison to the frequency of vibration |
| C. | its natural frequency is equal to the frequency of vibration |
| D. | measurement of vibratory motion is without any reference point |
| Answer» C. its natural frequency is equal to the frequency of vibration | |
| 62. |
Critical speed is expressed as |
| A. | rotation of shaft in degrees |
| B. | rotation of shaft in radians |
| C. | rotation of shaft in minutes |
| D. | natural frequency of the shaft |
| Answer» 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) |
| A. | resonance |
| B. | approximation |
| C. | superposition |
| D. | rayleigh quotient |
| Answer» 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 |
| A. | ωn |
| B. | 0.408ωn |
| C. | 0.204ωn |
| D. | 0.167ωn |
| Answer» 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 |
| A. | 0.471 and 1.19 hz |
| B. | 0.471 and 7.48 hz |
| C. | 0.666 and 1.35 hz |
| D. | 0.666 and 8.50 hz |
| Answer» A. 0.471 and 1.19 hz | |
| 66. |
5 m/s. |
| A. | 4.19 |
| B. | 5 |
| C. | 3.49 |
| D. | 3.36 |
| Answer» C. 3.49 | |
| 67. |
Which of the following expression represent the angular acceleration α of the connecting rod? |
| A. | −ω2 . sin θ/n |
| B. | −ω2 . cos θ.n |
| C. | ω2. cos θ/n |
| D. | ω2 . sin θ.n |
| Answer» A. −ω2 . sin θ/n | |
| 68. |
While calculating angular acceleration of the connecting rod, sin2(θ) term is neglected. |
| A. | true |
| B. | false |
| Answer» 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. |
| A. | 10.3 |
| B. | 11.1 |
| C. | 12.2 |
| D. | 11.8 |
| Answer» B. 11.1 | |
| 70. |
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. bending stress | |
| 71. |
Longitudinal vibrations are said to occur when the particles of a body moves |
| A. | perpendicular to its axis |
| B. | parallel to its axis |
| C. | in a circle about its axis |
| D. | none of the mentioned |
| Answer» B. parallel to its axis | |
| 72. |
When a body is subjected to transverse vibrations, the stress induced in a body will be |
| A. | shear stress |
| B. | tensile stress |
| C. | compressive stress |
| D. | none of the mentioned |
| Answer» B. tensile stress | |
| 73. |
The factor which affects the critical speed of a shaft is |
| A. | diameter of the disc |
| B. | span of the shaft |
| C. | eccentricity |
| D. | all of the mentioned |
| Answer» 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 |
| A. | damping factor |
| B. | damping coefficient |
| C. | logarithmic decrement |
| D. | magnification factor |
| Answer» D. magnification factor | |
| 75. |
Which of the following systems produce a vibration in the foundation? |
| A. | unbalanced machine |
| B. | balanced machine |
| C. | coupled machine |
| D. | uncoupled machine |
| Answer» 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. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 77. |
Which of the following is a type of transmitted force to the foundation? |
| A. | damping force |
| B. | undamping force |
| C. | tensile force |
| D. | torsional force |
| Answer» 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? |
| A. | 0 |
| B. | 1/2 |
| C. | 1/4 |
| D. | infinity |
| Answer» D. infinity | |
| 79. |
If isolation factor is negative, then what is the phase difference between transmitted and disturbing force? |
| A. | 180° |
| B. | 90° |
| C. | 450° |
| D. | 360° |
| Answer» A. 180° | |
| 80. |
Which of the following is true regarding Ɛ>1? |
| A. | transmitted force is greater than applied force |
| B. | transmitted force is less than applied force |
| C. | spring force is less than applied force |
| D. | damping force is less than applied force |
| Answer» A. transmitted force is greater than applied force | |
| 81. |
Isolation factor is twice the transmissibility ratio. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 82. |
The height of a Watt’s governor is |
| A. | directly proportional to speed |
| B. | directly proportional to (speed) |
| C. | inversely proportional to speed |
| D. | inversely proportional to (speed) |
| Answer» D. inversely proportional to (speed) | |
| 83. |
A Watt’s governor can work satisfactorily at speeds from |
| A. | 60 to 80 r.p.m |
| B. | 80 to 100 r.p.m |
| C. | 100 to 200 r.p.m |
| D. | 200 to 300 r.p.m |
| Answer» C. 100 to 200 r.p.m | |
| 84. |
When the sleeve of a Porter governor moves downwards, the governor speed |
| A. | increases |
| B. | decreases |
| C. | remains unaffected |
| D. | first increases and then decreases |
| Answer» B. decreases | |
| 85. |
In a Porter governor, the balls are attached to the extension of lower links. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 86. |
A Hartnell governor is a |
| A. | dead weight governor |
| B. | pendulum type governor |
| C. | spring loaded governor |
| D. | inertia governor |
| Answer» C. spring loaded governor | |
| 87. |
A Watt’s governor is a spring loaded governor. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 88. |
Which of the following is a pendulum type governor? |
| A. | watt’s governor |
| B. | porter governor |
| C. | hartnell governor |
| D. | none of the mentioned |
| Answer» 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 |
| A. | 1/2 iω2 |
| B. | iω2 |
| C. | 1/2 iωωp |
| D. | iωωp |
| Answer» 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 |
| A. | to dip the nose and tail |
| B. | to raise the nose and tail |
| C. | to raise the nose and dip of the tail |
| D. | to dip the nose and raise the tail |
| Answer» C. to raise the nose and dip of the tail | |
| 91. |
The steering of a ship means |
| A. | movement of a complete ship up and down in vertical plane about transverse axis |
| B. | turning of a complete ship in a curve towards right or left, while it moves forward |
| C. | rolling of a complete ship side-ways |
| D. | none of the mentioned |
| Answer» 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. |
| A. | true |
| B. | false |
| Answer» 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. |
| A. | true |
| B. | false |
| Answer» A. true | |
| 94. |
The pitching of a ship is assumed to take place with simple harmonic motion. |
| A. | true |
| B. | false |
| Answer» 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. |
| A. | 46.548 kw |
| B. | 56.548 kw |
| C. | 66.548 kw |
| D. | 76.548 kw |
| Answer» B. 56.548 kw | |
| 96. |
6 x 10 = 6 rad/s. |
| A. | 2.055 m |
| B. | 3.055 m |
| C. | 4.055 m |
| D. | 5.055 m |
| Answer» 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. |
| A. | 10.69 knm |
| B. | 20.69 knm |
| C. | 30.69 knm |
| D. | 40.69 knm |
| Answer» 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. |
| A. | 61.16 up |
| B. | 61.16 down |
| C. | 51.15 up |
| D. | none of the mentioned |
| Answer» A. 61.16 up | |
| 99. |
The steering of a ship means |
| A. | movement of a complete ship up and down in vertical plane about transverse axis |
| B. | turning of a complete ship in a curve towards right r left, while it moves forward |
| C. | rolling of a complete ship sideways |
| D. | none of the mentioned |
| Answer» 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 |
| A. | to move the ship towards starboard |
| B. | to move the ship towards port side |
| C. | to raise the bow and lower the stern |
| D. | to raise the stern and lower the bow |
| Answer» A. to move the ship towards starboard | |
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