Quiznetik

Dynamics of Machines | Set 2

1. Which of the following is true regarding Ɛ>1?

Correct : A. transmitted force is greater than applied force

2. Isolation factor is twice the transmissibility ratio.

Correct : B. false

3. The height of a Watt’s governor is

Correct : D. inversely proportional to (speed)

4. A Watt’s governor can work satisfactorily at speeds from

Correct : A. 60 to 80 r.p.m

5. The ratio of height of Porter governor to the height of Watt’s governor is

Correct : C. m + m/m

6. When the sleeve of a porter governor moves upwards, the governor speed

Correct : A. increases

7. When the sleeve of a Porter governor moves downwards, the governor speed

Correct : B. decreases

8. In a Porter governor, the balls are attached to the extension of lower links.

Correct : A. true

9. A Hartnell governor is a

Correct : C. spring loaded governor

10. A Watt’s governor is a spring loaded governor.

Correct : B. false

11. Which of the following is a pendulum type governor?

Correct : A. watt’s governor

12. The axis of precession is                          to the plane in which the axis of spin is going to rotate.

Correct : B. perpendicular

13. 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

14. 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

15. The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the right. The effect of gyroscopic couple on the aeroplane will be to dip the nose and raise the tail.

Correct : A. true

16. The steering of a ship means

Correct : B. turning of a complete ship in a curve towards right or left, while it moves forward

17. The rolling of a complete ship side-ways is known as pitching of a ship.

Correct : B. false

18. 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

19. The pitching of a ship is assumed to take place with simple harmonic motion.

Correct : A. true

20. When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

Correct : A. to move the ship towards star-board

21. It is required to lift water at the top of a high building at the rate of 50 litres/min. Assuming the losses due to friction equivalent to 5 m and those due to leakage equal to 5 m head of water, efficiency of pump 90%, decide the kilowatt capacity of motor required to drive the pump.

Correct : C. 0.302 kw

22. 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

23. The flywheel of an engine has a mass of 200 kg and radius of gyration equal to 1 m. The average torque on the flywheel is 1200 Nm. Find the angular acceleration of flywheel and the angular speed after 10 seconds starting from rest.

Correct : D. 6 rad/s

24. 6 x 10 = 6 rad/s.

Correct : A. 2.055 m

25. 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

26. 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

27. The steering of a ship means

Correct : B. turning of a complete ship in a curve towards right r left, while it moves forward

28. When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

Correct : A. to move the ship towards starboard

29. 24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

Correct : B. 1.42 m

30. 24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m ; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

Correct : C. 59.5

31. 24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

Correct : B. 17.824

32. 24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m ; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

Correct : B. 19064 n

33. 66.

Correct : B. 3/2 c) 3/4

34. The starting torque of the steam engine is 1500 N-m and may be assumed constant, using this data find the angular acceleration of the flywheel in rad/s2.

Correct : B. 0.6

35. 1m then find the other balancing mass situated at a distance of 0.2m.

Correct : D. 10

36. 1m. One of the balancing mass is 30 Kg with RoR of 10cm.

Correct : B. 35

37. 2m and r=0.3m, l=1m, find l2.

Correct : A. 0.26m

38. 2m and r=0.3m, l=1m, find l2.

Correct : D. 0.13m

39. 3m, l=1m, find l2 = 0.5m, find r1 in m.

Correct : B. 0.75

40. 2m, 0.15m, 0.25m and 0.3m. Angles between consecutive masses = 45, 75 and 135 degrees.

Correct : A. 116

41. 2m, 0.15m, 0.25m and 0.3m. Angles between consecutive masses = 45, 75 and 135 degrees.

Correct : A. 201.48

42. The system is automatically statically balanced.

Correct : D. 1, 3 and 4 only

43. 6m c = 2/3

Correct : A. 6978

44. 6m c = 2/3

Correct : A. 13956

45. 6m c = 2/3

Correct : A. -6978

46. 5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?

Correct : B. 836

47. 5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?

Correct : B. 1672

48. 5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in kN?

Correct : B. 2.508

49. 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

50. 1 mm.

Correct : D. 0.6

51. Calculate the natural longitudinal frequency in Hz.

Correct : A. 575

52. 01mm.

Correct : B. 49.85

53. Determine the frequency of transverse vibrations of the shaft.

Correct : D. 41

54. Determine the static deflection of the shaft in mm.

Correct : A. 0.147

55. 665×10-3m, calculate the critical speed of the shaft in rps. Centre of disc at 0.25m away from centre of axis of shaft.

Correct : D. 12.2

56. 5 m. Find the natural frequency of torsional vibrations.

Correct : A. 5.32

57. 6m, l2=0.5m, l3=0.4m

Correct : A. 8.95

58. 85m, kb = 0.55m C = 80 GN/m2

Correct : A. 3.37

59. 095m, d2=0.06m, d3=0.05m Ma = 900 Kg, Mb = 700 Kg

Correct : A. 0.855m

60. 05, 0.06, 0.07.

Correct : D. 0.08

61. 5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a single node system in Hz if the mass moment of inertia of rotors in Kg- m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2

Correct : A. 171

62. 5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a two node system in Hz if the mass moment of inertia of rotors in Kg- m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2

Correct : D. 277

63. Neglecting the inertia of shaft and gears calculate the frequency of free torsional vibrations in Hz.

Correct : A. 4.7

64. 5 and the mean speed is 20 rpm, find the maximum speed.

Correct : B. 25 rpm

65. 5 and the mean speed is 20 rpm, find the minimum speed.

Correct : A. 15 rpm

66. 3 m. The engine rotates at 2400 r.p.m. clockwise when viewed from the rear. Find the gyroscopic couple on the aircraft.

Correct : A. 10.046 kn-m

67. 6 m. It rotates at 1800 r.p.m. clockwise, when looking from the stern. Determine the gyroscopic couple, if the ship travels at 100 km/hr and steer to the left in a curve of 75 m radius.

Correct : B. 200.866 kn-m