Page 1 : MOCK TEST, BE- DYNAMICS OF MACHINERY, Q. 1. When a rigid body is suspended vertically and it oscillates with a small amplitude under the, action of the force of gravity, the body is known as, (A) simple pendulum, (B) torsional pendulum, (C) compound pendulum, (D) second’s pendulum, Q.2. The motion completed during one time period is known as(A) period of vibration, (B) cycle, (C) frequency, (D) all of the above, Q.3. Find the displacement in mm of the free longitudinal vibrations if the Natural frequency is 15 Hz., (A) 1.1, (B) 1.2, (C) 1.3, (D) 1.4, Q.4. A vertical spring-mass system has a mass of 0.5 kg and an initial deflection of 0.2 cm. Find the, spring stiffness., (A) 345 N/m, (B) 245 N/m, (C) 3452 N/m, (D) 2452 N/m, Q.5. An increase in the mass moment of inertia results in in vibration frequency., (A) increase, (B) decrease, (C) unchanged, (D) none of the above, Q.6. If the damping factor for a vibrating system is unity, then the system will be, (A) overdamped, (B) underdamped, (C) critically damped, (D) without vibrations

Page 2 : Q.7. 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(A) x1/x2, (B) log (x1/x2), (C) log (x1.x2), (D) log (x1+x2), Q.8. The speed at which the shaft runs so that the additional deflection from the axis of rotation of the, shaft becomes infinite, is known as, (A) Whirling speed, (B) Rotational speed, (C) Stabilizing speed, (D) Reciprocating speed, Q.9. Which of the following systems produce a vibration in the foundation?, (A) Unbalanced machine, (B) Balanced machine, (C) Coupled machine, (D) Uncoupled machine, Q.10. If the damper is not provided and the system is in resonance, which of the following is the, correct isolation factor?, (A) 0, (B) 0.5, (C) 0.25, (D) Infinite, Q.11. Maximum displacement due to forced vibration is the displacement due to static force., (A) inversely proportional to, (B) directly proportional to, (C) independent of, (D) none of the above, Q.12. The factor which affects the critical speed of a shaft is, (A) the diameter of the disc, (B) the span of the shaft, (C) eccentricity, (D) all of these, Q.13. If the isolation factor is negative, then what is the phase difference between transmitted and, disturbing force?

Page 3 : (A) 90°, (B) 180°, (C) 360°, (D) 720°, Q.14. Magnification factor is the ratio of _, (A) zero frequency deflection and amplitude of steady state vibrations, (B) amplitude of steady state vibrations and zero frequency deflection, (C) amplitude of unsteady state vibrations and zero frequency distribution, (D) none of the above, Q.15. 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, Q.16. In steady state forced vibrations, the amplitude of vibrations at resonance is Damping, coefficient., (A) equal to, (B) directly proportional to, (C) inversely proportional to, (D) independent of resonance, Q.17. A shaft carrying three rotors will have, (A) no node, (B) one node, (C) two nodes, (D) three nodes, Q.18. A disc is having a mass of 500 kg at a radius of gyration of 450 mm. What will be the value of, the mass moment of inertia of the shaft?, (A) 75.25, (B) 91.25, (C) 101.25, (D) 121.25, Q.19. For a gearing system, the equivalent system is made consisting of two rotors. How many nodes, will this new equivalent system have?, (A) 3, , (B) 2, , (C) 1, , (D) 0

Page 4 : Q.20. What is meant by node point?, (A) The point at which amplitude of vibration is maximum, (B) The point at which amplitude of vibration is zero, (C) The point at which amplitude of vibration is minimum, (D) None of the above, Q.21. For occurrence of free torsional vibration which of the condition is necessary?, (A) Rotors moving in same direction, (B) Rotors having same frequency, (C) Rotors having different frequency, (D) Rotors rotate in the same sense, Q.22. In which of the following condition torsional vibration will not take place, considering 3 rotors, A, B and C. A is rotating in clockwise direction., (A) B in clockwise C in anticlockwise, (B) C in clockwise B in anticlockwise, (C) B and C in clockwise, (D) B and C in anticlockwise, Q.23. Keeping the mass moment of inertia of left end and the right end shafts in a three-rotor system, same, if the length of one shaft is doubled what should be the effect on the length of other shaft?, (A) Doubled, , (B) Halved, , (C) Constant, , (D) Increased to 4 times, , Q.24. The unbalanced primary couple caused due to reciprocating mass of each cylinder is given as, (A) m r l ω2 cos θ, , (B) m r l ω (cos θ / n), , (C) m r l ω2 cos 2θ, , (D) m r ω2 cos 2θ, , Q.25. Which of the following conditions should be satisfied for complete balancing of multi-cylinder, inline engines?, (A) Primary couples should be balanced, (B) Secondary couples should be balanced, (C) Both a. and b., (D) None of the above, Q.26. Secondary force in reciprocating engine mechanism is caused due to (A) S.H.M. of reciprocating parts, (B) oscillation of reciprocating parts, (C) obliquity of arrangement of reciprocating parts, (D) all of the above

Page 5 : Q.27. The unbalanced force caused due to reciprocating mass is given by the equation(A) mrω2 sin θ + mrω2 (sin 2θ/n), (B) mrω2 sin θ + mrω2 (cos 2θ/n), (C) mrω2 cos θ + mrω2 (cos 2θ/n), (D) mrω2 (sin θ + sin 2θ/n), Q.28. Often an unbalance of forces is produced in rotary or reciprocating machinery due to the _, (A) Centripetal forces, , (B) Centrifugal forces, , (C) Friction forces, , (D) Inertia forces, , Q.29. The mass used to balance the mass defect is known as (A) Balancing mass, , (B) Defect mass, , (C) Replacement mass, , (D) Fixing mass, , Q. 30. Let the disturbing mass be 100 kg and the radius of rotation be 10 cm and the rotation speed be, 50 rad/s, then calculate the centrifugal force in kN., (A) 50, , (B) 25, , (C) 50000, , (D) 25000, , Q.31 In balancing of single-cylinder engine, the rotating unbalance is (A) completely made zero and so also the reciprocating unbalance, (B) completely made zero and the reciprocating unbalance is partially reduced, (C) partially reduced and the reciprocating unbalance is completely made zero, (D) partially reduced and so also the reciprocating unbalance, Q.32. The primary unbalanced force is maximum when the angle of inclination of the crank with the, line of stroke is(A) 0°, , (B) 90°, , (C) 180°, , (D) 360°, , Q.33. What is the effect of partial balancing of the reciprocating parts?, (A) Unbalanced primary force, (B) Unbalanced secondary force, (C) Balanced primary force, (D) Balanced secondary force, Q.34. Temperature monitoring technique uses which of the following devices to measure temperature, of the machining surfaces?, (A) Pyrometers, , (B) Thermocouples, , (C) Thermometers, , (D) All of the above, , Q.35. Which type of instruments do not require separate power source for measuring vibratory, response of a vibratory system?, (A) Active instruments, , (B) Passive instruments, , (C) Both a. and b., , (D) None of the above

Page 6 : Q.36. Which of the following instruments measure amplitude of a vibrating body?, (A) Vibrometers, , (B) Seismometer, , (C) Both a. and b., , (D) None of the above, , Q.37. Which of the following vibrometers have frequency ratio (ω/ωn) << 1?, (A) Accelerometers, , (B) Velometers, , (C) Both a. and b., , (D) None of the above, , Q.38. In graph of (Transmissibility vs Frequency Ratio) shown below, the shaded region is called as, , (A) Spring controlled region, , (B) Damping controlled region, , (C) Mass controlled region, , (D) None of the above, , Q.39. What is the function of the controller in active vibration isolation systems?, (A) Detect vibrations to be controlled, , (B) Reposition the masses, , (C) Interpret detected vibrations and execute commands, , (D) All of the above, , Q.40. In FFT Analyzer, the digital signals converted into analog signals and send to the(A) cathode ray oscilloscope, , (B) cathode ray tube, , (C) anode ray oscilloscope, , (D) anode ray tube, , Q.41. Which instrument is used to record building vibrations or vibrations of huge structures like, railway bridges?, (A) Stroboscope, , (B) Accelerometer, , (C) Vibrometer, , (D) None of the above, , Q.42. In vibrometer, the relative motion between the mass and vibrating body is converted into, proportional(A) current, , (B) voltage, , (C) resistance, , (D) ampere

Page 7 : Q.43. Find the incorrect match, (A) Middle ear – amplifies sound waves, (B) Hair cells – present on basilar membrane, (C) Saccule and utricle – maintain static equilibrium, (D) Cristae – perform hearing function, Q.44. Which instrument integrates sound pressure as a function of time over a period of time?, (A) Noise dosimeter, , (B) FFT analyzer, , (C) Both a. and b., , (D) None of the above, , Q.45. The scale to measure the intensity level of sound is called, (A) vector scale, , (B) measuring ruler, , (C) bel scale, , (D) decibel scale, , Q.46. In a market, the intensity level of sound recorded is 80 dB, the intensity level of sound should, be(A) 10-4 Wm-2, , (B) 10-6 Wm-2, , (C) 10-8Wm-2, , (D) 10-5 Wm-2, , Q.47. When sound is incident on the surface of a medium it bounces back into the first medium. The, phenomenon is called (A) refraction of sound, , (B) deflection of sound, , (C) defraction of sound, , (D) reflection of sound, , Q.48. The loudness and amplitude of sound varies, (A) directly, , (B) inversely, , (C) Not related, , (D) Proportionally, , Q.49. Which part of the human ear is divided by the basilar membrane?, (A) Ear drum, , (B) Helicontrema, , (C) Cochlea, , (D) Eustachian tube, , Q.50. To find the speed of sound, we use the relation, (A) v = fλ, , (B) f = vλ, , (C) lambda = fv, , (D) v = f + lambda;