Quiznetik

Applied Mechanics | Set 2

1. Which of the following statement is incorrect?

Correct : C. A body in motion will always have kinetic energy more than the potential energy

2. The value of acceleration due to gravity is 980 cm/sec2. Its value in meter per (hour)2 will be

Correct : A. 1.27 x 108

3. The torque acting on a system is zero. Which of the following will be conserved?

Correct : D. Angular momentum

4. Our weight will be zero under all of the following conditions EXCEPT

Correct : C. When we are ascending in a lift with acceleration of 4.9 m/s2

5. A clock with a second pendulum is gaining 5 minutes a day. To correct it

Correct : D. The length of the pendulum should be increased

6. Which of the following is not a projectile?

Correct : D. Throwing a cricket ball from one player to another

7. The piston of a steam engine moves in S.H.M. The crank rotates at 180 r.p.m. and the stroke length is 2 metres. The linear velocity of the piston when it is at a distance of 1 metre from the centre is

Correct : E. Zero

8. A cage weighing 200 kg is lowered down a mine shaft with uniform acceleration. In the first 5 sec the cage reaches a depth of 20 m. The tension in the cord lowering the cage would be

Correct : B. 167.2 kg

9. Static friction is always

Correct : A. greater than the dynamic driction

10. Which of the following bearing will have least coefficient of friction

Correct : E. Tapered bearing

11. The dimensions of power are

Correct : D. ML2T-3

12. A body is executing simple harmonic motion of amplitude 1 cm. Its velocitywhile passing through the central point is 10 mm/sec. Its frequency will be

Correct : C. 1 rps

13. Which of the following is dimensionless?

Correct : C. Specific gravity

14. If two bodies one light and one heavy have equal kinetic energies, which one has a greater momentum?

Correct : B. Heavy body

15. A car travelling at a speed of 60 km/hour is braked and comes to rest 6 seconds after the brakes are applied. The minimum coefficient of driction between the wheels and the road would be

Correct : C. 0.283

16. A man weighing 60 kg jumps on a vehicle of weight 240 kg moving with a velocity of 36 km/hours. The velocity of the vehicle after the man has jumped would be

Correct : A. Less than 3.6 km/hour

17. How many coins 0.75 cm in diameter and 1/8 cm thick must be malted down to form a rectangular solid whose edges are 5 cm. 4 cm and 3 cm?

Correct : B. 1087

18. The gravitational field intensity is maximum at the

Correct : E. centre of the earth

19. A ball of mass 1 kg moving with a velocity of 2 m/sec collides directly with a stationary ball of mass 2 kg. If the first ball comes to rest after the impact the velocity of second ball after impact will be

Correct : E. 1.0 m/sec

20. A particle moves along a rough plane inclined at 30? to the horizontal. The co-efficient of friction between the particle and the plane is 0.1. Its initial velocity is 15 m/sec. The ratio of the velocity of the particle when it move down the plane to that when it move up the plane would be in the regions

Correct : B. 5 ? 7

21. In case of cantilever, irrespective of the type of loading the maximum bendry moment and maximum shear force occur at

Correct : E. Fixed end

22. A beam fixed at both ends with a central load W in the middle will have zero bending moment at

Correct : B. two places

23. If the positive and negative shear force diagram areas are not equal, it can be concluded that

Correct : B. there is at least one couple acting on the beam

24. One joule is equal to

Correct : D. 107 ergs

25. A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is

Correct : C. Determinate but depends on the acceleration of the cylinder

26. The forces which meet at one point but their lines of action do not lie in one plane, are called

Correct : C. Intersecting forces

27. The common acceleration will be

Correct : B. 1.0 m/s2

28. The locus of instantaneous centre of a moving rigid body

Correct : E. Centrode

29. When all the forces acting on a body lie in one plane and their lines of action meet at one point, the forces

Correct : C. are known as coplaner-concurrent forces.

30. A force F = 2i + 3j - k is passing through the origin. Its moment about point (1, 1, 0) is

Correct : C. i - j - k

31. Efficiency of a screw jack in maximum when its 31 helix angle, ? is

Correct : D. 45 - ?/2

32. When two concurrent and coplaner forces P and Q act at an angle of 180?, their resultant will be a

Correct : C. (P-Q)

33. A man lifts a stone weighting 300 g from the ground to a height of 2m and throws it horizontally with a velocity of 6 m/sec. The work done by the man is

Correct : B. 11.286 J

34. A body of weight 100 kg is placed on a horizontal plane. A horizontal force of 30 kg is applied and the block is just on the point of motion. The angle of friction is

Correct : A. About 16?

35. If the above tape weights 0.001 kg/ft, sag is

Correct : C. 2.90 ft

36. A body whose true weight is 14 kg appears to weigh 15 kg when weighed with the help of a spring balance in a moving lift. The acceleration of the lift at the time was

Correct : B. 0.7 m/sec2

37. Which of the following pair will have identical dimensions?

Correct : C. Momentum and force

38. A particle is moving in Simple Harmonic Motion in a simple pendulum with some period of oscillation. Now in order to double the period of oscillation

Correct : A. The length of pendulum should be quadrupled

39. Under which circumstances will have zero velocity and be still accelerating?

Correct : D. A ball at its highest point of its rise when thrown up

40. Newton, dyne and poundal are known as

Correct : D. absolute units

41. ML2T-2 could be the dimension of

Correct : B. moment of force

42. The moving parts of a machine which weigh 1 tonne perform vertical simple harmonic motion with an amplitude of 2.5 cm and a period of 0.5 sec. The base of the machine weighs 3 tonnes and rests on the ground. Maximum reactions on the ground would be

Correct : E. 4.4 tonnes

43. A ball is allowed to fall freely from a height of 3 metres on to a fixed plate. If the successive rebound heights are h1, h2, h3

Correct : A. 5 metres

44. In the above problem, acceleration of crooshead at 30? phase equals

Correct : E. 870 m/s2

45. If a particle charges its angular velocity from 30 to 35 rpm in 20 seconds then it has angular acceleration of

Correct : E. 15 rev/min2

46. Power required for a train weighing 200 Mg to move at a uniform speed of 60 Kmph up an incline of 1 in 200 is (Resistance due to friction is negligible)

Correct : B. 163.5 KW

47. If air resistance is neglected, at the mid-point of its swing, the acceleration of the bob of a simple pendulum along its path is always

Correct : D. Decreasing

48. The force which produces an acceleration of 1 m/sec2 in a mass of 1 kg is called

Correct : B. one Newton

49. The maximum efficiency of a scres jack having square threads and friction angle of 30 degree will be

Correct : D. 33%

50. Water rises in a capillary tube to a height h. It will rise to a height more than h.

Correct : E. on the surface of moon

51. The centre of gravity of a plane lamina will not be at its geometrical centre if it is a

Correct : E. Right angled triangle

52. Coulomb friction is

Correct : D. Friction between dry surfaces

53. A framed structure is perfect if it contains members equal to

Correct : B. 2n - 3

54. Coulomb's law for the force between electric charges most closely resembles

Correct : D. Newton's law of gravitation

55. A number of forces acting at a point will be in equilibrium if

Correct : D. None of the above

56. The springs A and B are identical except that A is stiffer than B, that is KA > kB. If both the springs are stretched by the same amount

Correct : A. more work will be expended on A than B

57. A rigid body is suspended vertically at a point and oscillates with a small amplitude under the action of the force of gravity. Such an arrangement is called

Correct : D. Compound pendulum

58. A block slides down a frictionless incline making an angle ? with an elevator floor. The acceleration relative to the incline will be maximum when

Correct : D. elevator descends with deceleration a

59. An automobile is travelling at 25 m/s. It takes 0.3 second to apply the brakes after which the deceleration is 6 m/s2. How far, in meters, does the automobile travel before it stops?

Correct : E. 60

60. A single purchase crab has a handle 45 cm long and a drum of 25 cm diameter. The pinion has 30 teeth and spur has 150 teeth. The efficiency of the machine is 75%. If the maximum force that can be applied is 500 newtons, the maximum load that can be lifted will be

Correct : B. 6750 N

61. A body in Simple Harmonic Motion will attain maximum velocity when it passes through

Correct : E. Mean position

62. A body of weight W is resting at a plane inclined at 30? to the horizontal. It is attached to a string making an angle of 60? with horizontal. If the angle of friction be 30? the tension in the string would be

Correct : C. W/2

63. A 5 m ladder of mass 25 kg is placed in a position where its inclination to a vertical wall is at 30?. A 100 kg man is to climb the ladder. If the coefficient of static friction is 0.25 the height along ladder at which the slipping will be induced would be

Correct : C. 0.8 m

64. Which one of the following is not the law of dry friction?

Correct : D. The force of friction is always normal to the surface

65. A 3.2 m diameter balloon is filled with Helium. The total weight of balloon, gas and pay load is 10 kg kg. In an isothermal atmosphere having conditions identical to N.T.P. the balloon will rise to a height of about

Correct : A. 6000 m

66. The statement the resultant of the external forces applied to a body (rigid or non-rigid) composed of a system of particles is equivalent to the vector summation of the effective forces acting on all particles-is known as

Correct : C. D' Alembert's principle

67. The moment of a force

Correct : D. Measures the ability to produce turning or twisting about an axes

68. In a slider crank mechanism, the crank is rotating at 200 rpm. If length of connecting rod is 8 mts and crank shaft is 2 mts, velocity of crosshead at 30? rotation of crank shaft equals.

Correct : E. 25.5 m/s

69. If the angle of friction is zero a body will experience

Correct : B. Zero friction

70. The excape velocity for the moon is nearly

Correct : D. 2.4 km/s

71. Williot-Mohr diagram is used to determine

Correct : D. deflection in trusses

72. A body is pushed with a force of 10 N for 0.5 second. The impulse given to the body is

Correct : D. 5 Ns

73. A couple applied to a flywheel of mass 5 kg and of radius of gyration 20 cm produces an angular acceleration of 4 radians/sec2. The torque applied in dyne cm is

Correct : B. 8 x 106

74. The tension T2 will be

Correct : E. 30 N

75. The number of revolutions through which a pulley will rotate from rest if its angular acceleration is increased uniformly from zero to 12 rad per sec2 during 4 sec and then uniformly decreased to 0 rad per sec2 during the next 3 sec would be

Correct : B. 26.74

76. The angular velocity of hour hand of a watch is

Correct : B. 0.0001455 sec-1

77. A plane is inclinea at angle ? to horizontal. If a body can just rest on a plane, determine the least force to draw the body up the plance

Correct : A. W sin2?

78. A stone is dropped into a deep shaft without any initial velocity. The sound of the stone hitting the bottom is heard after 4 seconds. If the velocity of sound is 330 m/sec the depth of the shaft will be

Correct : D. 66.2 m

79. Maximum acceleration in above problem is

Correct : E. 4?2/9 m/s2

80. A body weighing 500 kg falls 8 cm and strikes a 500 kg/cm spring. The deformation of the spring will be

Correct : C. 4 cm

81. Given that the area of a figure varies as square of mean ordinate. The area of the figure is 154 sq. cm when the mean ordinate is 7 cm. The area of the figure when mean ordinate is 10.5 cm will be

Correct : D. 346.5 cm

82. The weight of a 72 kg man on earth's surface is

Correct : D. 706.3 N

83. If four turms of rope around a horizontal post will hold a 100 kg weight with a pull of 1 kg, then

Correct : C. 0.18

84. In the second system of pulleys, if there are two pulley blocks having 'n1' and 'n2' pulleys in the first and second pulley blocks respectively, then the velocity ratio of the whole system will be equal to

Correct : B. n1 - n2

85. The power of a locomotive is 315 kW and the total weight of the train is 2000 kN. If the track resistance is 15 N per kN, the maximum speed that the locomotive can attain on level track will be

Correct : E. 38 kmph

86. A particle is of wieght 8 kg. When it is allowed to fall under the force of gravity its momentum at the time t = 2 sec would be

Correct : D. 16 kg sec

87. The maximum velocity of a body in SHM with amplitude of 150 mm and a frequency 2 vibrations/sec is equal to

Correct : A. 1.885 m/sec

88. A wheel 8 mts in diameter coasts to rest from a speed of 800 rpm in 10 minutes. Its angular deceleration is

Correct : C. 502 rad/min2

89. The moment of inertia of a hollow circular section whose external diameter is 8 cm and interial diameter is 6 cm about the axis passing through its centre is

Correct : B. 137.5 cm4

90. A rope of weight 0.5 kg/m hangs from a drum for a height of 6 m. The work done in winding up the rope will be

Correct : A. 9 kg-m

91. The x coordinate of the centroid of the area enclosed by the parabolas y = x2 and x = y2 will be

Correct : D. 0.45

92. According to Kepler's law of motion the square of the time period T of a planet around the sun is proportional to the

Correct : C. cube of the mean distance of planet from sun

93. Let the only force acting on two bodies be their mutual interactions. If both bodies start from rest, the distances travelled by each will be a

Correct : C. inversely proportional to the respective masses of the bodies

94. Kinetic friction is

Correct : C. Friction force acting when the body is in motion

95. When two forces acting at a point are such that if the direction of one is reversed, the direction of the resultant is turned through a right angle, the forces must be

Correct : C. equal in magnitude

96. If w is the angular velocity of the pulley and T1 and T2 are tensions of driving and driven side then power transmitted equals

Correct : D. (T1 - T2) w

97. The ideal angle of banking provided on roads

Correct : A. Depends on (velocity)2 of vehicle

98. The moment of inertia of a thin ring about an axis perpendicular to plane of ring is

Correct : B. Mr2

99. A 2 kg block is dropped from a height of 4 metre onto a spring of force constant k = 1960 N/m. The spring will be compressed through

Correct : D. 8 cm

100. A boy sitting in a rail road car throws a ball straight up into the air. The ball will fall back into his hands when the rail road car is

Correct : A. moving at constant velocity