## TEST PAPER- 5 (MECHANICAL)

**HEAT TRANSFER**

** 1**. Unit of thermal conductivity in M. K. S units is

a) kcal / kg m 2 0 c b) kcal – m / hr m 2 0 c

c) kcal / hr m 2 0 C d) kcal – m / hr 0 C e) kcal – m / m 2 0 C

2. Unit of thermal conductivity in S.L units is

a) J/m 2 sec b) J / m 0 K sec

c) W / m 0 k d) (a) and (c) above e) (b) and (c) above

3. Thermal conductivity of soild metals with rise in temperature normally

a) increase b) decrease c) remains constant

d) may increase or decrease depending on temperature e) unpredictable

4. Thermal conductivity of non- metallic amorphous soilds with decrease in temperature

a) increase b) decrease c) remain constant

d) may increase or decrease depending on temperature e) unpredictable

5. Heat transfer takes place as per

a) Zeoth law of thermodynamics b) first law of thermodynamics

c) second law of the thermodynamics d) kirchoff ‘s law e) Stefan ‘s law

6. When heat is transferred from one particle of hot body to another by actual motion of the heated particles,

it is referred to as heat transfer by

a) conduction b) convection c) radiation

d) conduaction and convection e) convection and radiation

7. When heat is transferred form hot body to cold body, in a straight line, without affecting the

intervening medium, it is referred to as gheat transfer by

a) conduction b) convection c) radiation

d) conduaction and convection e) convection and radiation

8.Sensible heat is the heat required to

a) change vapour in to liquid b) change liquid in to vapour

c) increase the temperature of a liquid or vapour d) convert water in to steam and superheat it

e) convert saturated steam in to dry steam

9. The insulation ability of an insulator with the presence of moisture would

a) Increase b) decrease c) remain unaffected

d) may increase / decrease depending on temperature and thickness of insulation e) none of the above

10. When heat is transferred by molecular collision, it is referred to as heat transfer by

a) Conduction b) convection c) radiation d) scattering e) convection and radiation

11. Heat transfer in liquid and gases takes place by

a) Conduction b) convection c) radiation

d) conduction and convection e) convection and radiation

12. Which of the following is the case of heat transfer by radiation ?

a) blast furnace b) heating of building c) cooling of parts in furnace

d) heat received by a person from fireplace e) all of the above

13. Heat is closely related with

a) liquids b) energy c) temperature d) entropy e) enthalpy

14. Pick up the wrong case. Heat flowing from one side to other de3pends directly on

a) face area b) time c) thickness d) temperature difference e) thermal conductivity

15. Metals are good conductors of heat because

a) their atoms collide frequently b) their atoms are relatively far apart

c) they contain free electrons d) they have high density e) all of the above

16. Which of the following is a case of steady state heat transfer ?

a) I.C engine b) air preheaters c) heating of building in winter

d) all of the above e) none of the above

17. Total heat is the heat required to

A) change vapour in to liquid b) change liquid in to vapour

c) increase the temperature of a liquid or vapour d) convert water in to steam in to dry steam

e) convert saturated steam in to dry steam

18. Cork is a good insulator because it has

a) free electrons b) atoms colliding frequency c) low density

d) porous body e) all of the above

19. Thermal conductivity of water in genral with rise in temperature

a) increase b) decrease c) remains constant

d) may increase or decrease depending on temperature e) none of the above

20. Thermal conductivity of water at 200 C is of the order of

a) 0.1 b) 0.23 c) 0.42 d) 0.51 e) 0.64

21. Temperature of steam at around 540 0 C can be measured by

a) Thermometer b) radiation pyrometer c) thermistor

d) Thermocouple e) thermopile

22. Thermal conductivity of air at room temperature in Kcal / m hr 0 C is of the order of

a) 0.002 b) 0.02 c) 0.01 d) 0.1 e) 0.5

23. The time constant of a thermocouple is

a) The time taken to attain the final temperature to be measured

b) The time taken to attain 50 % of the value of ini tail temperature difference

c) The time taken to attain 63.2 % of the value of initial temperature difference

d) Determined by the time taken to reach 1000 C from 00 C

e) None of the above

24. Thermal conductivity of air with rise in temperature

a) Increase b) decrease c) remains constant

d) May increase or decrease depending on temperature e) none of the above

25. Heat flows from one body to other when they have

a) different heat constents b) different specific heat c) different atomic structure

d) different temperatures e) none of the above

26. The concept of overall coefficient of heat transfer is used in heat transfer problems of

a) Conduction b) convection c) radiation

d) all of the three combined e) conduction and convection

27. In heat transfer, conductance equals conductivity ( kcal/ hr/sqm /0C/ cm) divided by

a) Hr ( time ) b) sqm ( area) c) 0 C ( temperature )

d) cm ( thickness) e) kcal ( heat)

28. The amount of heat flow through a body by conduction is

a) directly proportional to the surface area of the body

b) directly proportional to the temperature difference on the two faces of the body

c) dependent upon the material of the body

d) inversely proportional to the thickness of the body e) all of the above

29. Which of the following has least value of conductivity?

a) glass b) water c) plastic d) rubber e) air

30. Which of the following is expected to have highest thermal conductivity ?

a) steam b) solid ice c) melting ice d) water e) boiling water

31. Thermal conductivity of glass- wool varies from sample to sample because of variation in

a) composition b) density c) porosity d) structure e) all of the above

32. Thermal conductivity of a material may be defined as the

a) quantity of heat flowing in one second through one cm cube of material when opposite faces are maintained at a temperature difference of 1 0 C

b) quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1 0 C

c) heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces

d) all of the above e) none of the above

33. Which of the following has maximum value of thermal conductivity ?

a) aluminum b) steel c) brass d) copper e) lead

34. Moisture would find its way in to insulation by vapour pressure unless it is prevented by

a) high thickness of insulation b) high vapour pressure

c) less thermal conductivity insulator d) a vapour seal e) all of the above

35. Heat is transferred by all three modes of transfer, *viz*, conduction, convection and radiation in

a) electric heater b) steam condenser c) melting of ice

d) refrigerator condenser coils e) boiler

36.According to prevost theory of heat exchange

a) it is impossible to transfer heat from low temperature source to high temperature source

b) heat transfer by radiation requires no medium

c) all bodies above absolute zero emit radiation

d) heat transfer in most of the cases takes place by combination of conduction, convection and radiation

e) rate of heat transfer depends on thermal conductivity and temperature difference

37. The ratio of heat flow Q1/ Q2 from two walls of same thickness having their thermal conductivities as K1 = 2 K 2 will be

a) 1 b) 0.5 c) 2 d) 0.25 e) 4

38. Heat transfer by radiation mainly depends upon

a) its temperature b) nature of the body c) kind and extant of its surface

d) all of the above e) none of the above

39. Thermal diffusivity is

a) a dimensionless parameter b) function of temperature

c) used as mathematical model d) a physical property of the material

e) useful in case of heat transfer by radiation

40. Thermal diffusivity of a substance is

a) proportional of thermal conductivity (k ) b) inversely proportional to K

c) proportional to (k) 2 d) inversely proportional to k 2

e) none of the above

41. Unit of thermal diffusity is

a) m2 / hr b) m2 /hr 0 C c) kcal/m2 hr

d) kcal/m. hr0C E) KCAL/ M2 HR 0 C

42. An electric furnace has a laminated wall composed of 0.2 m of refractory brick ( k = 2 ), 0.15 m of insulation ( k = 0.15 ), and 0.15 m of brick having ( k = 1.5 ) Inner and outer temperatures of wall are 1027 0 C respectively. Units of k are kcal- m / hr m 2 0 C If surface area of the wall is 1.2 m 2, heat transfer rate will be

a) 10 kcal /hr b) 100 kcal/hr c) 1000 kcal/hr d) 10,000 kcal/hr e) none of the above

43. Thermal conductivity of wood depends on

a) moisture b) density c) temperature d) all of the above e) none of the above

44. In convection heat transfer from hot flue gasses to water tube, even though flow may be turbulent, a laminar flow region ( boundry layer of flim ) exists close to the tube . The heat transfer through this flim takes palce by

a) convection b) radiation c) conduction d) both convection and coeducation e) none of the above

45. Flim coefficient is defined as

a) Inside diameter of tube b) Thermal conductivity

Equivalent thickness of film Equivalent thickness of film

c) Specific heat X Viscocity

Thermal conductivity or Molecular diffusivity of momentum

Thermal diffusivity

d) Film coefficient X Inside diameter e) none of the above

Thermal conductivity

46.Heat conducted through unit area and unit thick face per unit time when temperature difference between opposite face is unity , is called

a) thermal resistance b) thermal coefficient c) temperature gradient

d) thermal conductivity e) heat – transfer

47. In the heat flow equation Q = KA ( t1 – t 2) / X , the tern t 1 – t 2 / x is known as

a) thermal resistance b) thermal coefficient c) temperature gradient

d) thermal conductivity e) heat – transfer

48. In the heat flow equation Q= KA ( t1 – t2 )/ x , the term t1 – t2 / x is known as

a) thermal resistance b) thermal coefficient c) temperature gradient

d) thermal conductivity e) heat- transfer

49. The rate of energy emission from unit surface area through unit soild angle, along a normal to the surface , is known as

a) Emissivity b) transmissivity c) reflectivity

d) intensity of radiation e) absorptivity

50. Emissivity of a white polished body in comparison to a black body is

a) higher b) lower c) same

d) depends upon the shape of body e) none of the above

51. A grey body is one whose absorptivity

a) varies with temperature b) varies with wavelength of the incident ray c) is equal to its emissivity

d) does not vary with temperature and wavelength of the incident ray e) none of the above

52. Eckert number is expressed

a) ( velocity of fluid ) 2

( Specific heat at constant pressure X temperature )

b) X Coefficient of visocity )

Thermal conductivity

c) X Linear dimension )

Thermal conductivity

d) Density X Velocity X Linear dimension

Coefficient of absolute viscosity

53. Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of

a) 1 : 1 b) 2 : 1 c) 1 : 2 d) 4 : 1 e) 1 : 4

54. Grashoff number is expressed by

a) Inside diameter of tube b) Thermal conductivity

Equivalent thickness of film Equivalent thickness of film

c) Specific heat X Viscosity

Thermal conductivity or d) Film coefficient X Inside diameter

Molecular diffusivity of momentum Thermal conductivity

Thermal diffusivity

e) Inertia force X Buoyant force

Viscous force

55. A non- dimensional number generally associated with natural convection heat transfer is

a) Grashoff number b) Nusselt number c) Weber number

d) Prandtl number e) Reynolds number

56. LMTD in case of counter flow heat exchange as compared to parallel flow heat exchanger is

a) Higher b) lower c) same

d) depends on the area of heat exchanger e) depends on temperature conditions.

57. In heat exchangers, degree of approach is defined as the difference between temperatures of

a) cold water inlet and outlet b) hot medium inlet and outlet

c) hot medium outlet and cold water inlet d) hot medium outlet and cold water outlet

e) none of the above

58. In counter flow heat exchangers

a) both the fluids at inlet ( of heat exchanger where hot fluid enters ) are in their coldest state

b) both the fluids at inlet are in their hottest state c) both the fluids at exit are in their hottest state

d) one fluid is in hottest state and other in coldest state at inlet

e) any combination is possible depending on design of heat exchanger .

59. A steam pipe is to be insulated by two insulating materials put over each other . For best results

a) better insulation should be put over pipe and better one over it

b) inferior insulation should be put over pipe and better one over it

c) both may be put in any order

d) wheather to put inferior on over pipe or the better one would depend on steam temperature

e) unpredictable .

60. Nusselt number is expressed by

a) Inside diameter of tube b) Thermal conductivity

Equivalent thickness of film Equivalent thickness of film

c) Specific heat X Visocity Molecular diffusitivity of momentum

Thermal conducitivity or Thermal diffusivity

e) none of the above

61. Fourier’s law of heat conduction is valid for

a) one dimensional cases only b) two dimensional cases only c) three dimensional cases only

d) regular surface having non- uniform temperature gradients e) irregular surface

62. According of Kirchhoff’s law,

a) radient heat is proportional to fourth power of absolute temperature

b) emissive power depends on temperature

c) emissive power and absorptivity are constant for all bodies

d) ratio of emissive power to absorptive power is maximum for perfectly black body

e) ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body

63. All rediations in a black body are

a) reflected b) refracted c) transmitted d) absorbed e) partly reflected and partly absorbed

64. According to Kirchoff’s law , the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a

a) grey body b) brillent white polished body c) red hot body d) black body e) none of the above

65. The concept of overall coefficient of heat transfer is used in case of heat transfer by

a) conduction b) convection c) radiation d) conduction and convection e) convection and radiation

66. The unit of overall coeffient of heat transfer is

a) Kcal / m 2 b) Kcal / hr 0 C c) Kcal / m 2 hr 0 C d) Kcal / m hr 0 C e) Kcal / m3 hr 0 C

67. The heat transfer equation Q = *AT* 4 is known as

a) Fourier equation b) Laplace’s equation c) Poisson equation

d) genral heat transfer equation e) Stefan-Boltzmann equation

68. Joule sec is the unit of

a) universal gas constant b) Kinematic viscosity c) thermal conductivity d) Planck’s constant

69. The value of Prandtl number for air is about

a) 0.1 b) 0.3 c) 0.7 d) 1.7 e) 10.5

70. The value of the wavelength for maximum emissive power is given by

a) Wine’s law b) Planck’s law c) Stefan’s law d) Fourier law e) Kirchhoff ‘s law

71. Prandtl number is expressed by

a) Inside diameter of tube b) Thermal conductivity

Equivalent thickness of film Equivalent thickness of film

c) Specific heat X Viscosity Molecular diffusivity of momentum

Thermal conductivity or Thermal diffusivity

d) Film coefficient X Inside diameter

Thermal conductivity e) none of the above

72. Log mean temperature difference in case of counter flow compared to parallel flow will be

a) same b) more c) less d) depends on other factors e) none of the above

73. The energy distribution of an ideal reflector at higher temperature is largly in the range of

a) Shorter wavelength b) longer wavelength c) remains same at all wavelength

d) wavelength has nothing to do with it e) none of the above

74. Total emissivity of polished sliver compared to black body is

a) same b) higher c) more or less same d) very much lower e) very much higher

75. According to Stefan- Boltzmann law, dial rediators emit radiant energy at a rate proportional to

a) absolute temperature b) square of temperature c) fourth power of absolute temperature d) fourth power of temperature e) cube of absolute temperature

76. Which of the following property of air does not increase with rise in temperature

a) thermal conductivity b) thermal diffusivity c) density d) dynamic viscosity e) kinematic viscosity

77. The unit of Stefan Boltazmann constant is

a) watt/ cm 2 0 K b) watt/ cm 4 0 K c) watt / cm 2 0 K4 d) watt/ cm 2 0 K4 e) watt/ cm2 0 K 2

78. In free convection heat transfer, Nusselt number is funcation of

a) Grashoff no. and Reynolds no. b) Grashoff no. and Prandtl no c) Prandtl no and Reynolds no.

d) Grashoff no. , Prandtl no. and Reynold no. e) None of the above

79. Stefan Boltazmann law is applicable for heat transfer by

a) conduction b) convection c) radiation

d) conduction and radiation combined e) convection and radiation combined

80. The thermal diffusivities for gasses are generally

a) more than those for liquids b) less than those for liquids c) more than those for soilds d) dependent on the viscosity e) same as for the liquids

81. The thermal diffusivities for solids are generally

a) Less than those for gases b) less than those for liquids c) more than those for liquids and gases d) more or less same as for liquids and gases e) zero

82.Thermal diffusivity is expressed by the relation

a) K / C P b) Cp / K c) k / C d) C p / K e) k/ C p

where k = thermal conducvity

= density, = dynamic viscosity

And C p = Specific heat at constant pressure

83.Thermal diffusivity of a substance is

a) directly proportional to thermal conductivity b) inversely proportional to density of substance

c) inversely proportional to specific heat d) all of the above e) none of the above

84.If two surface of area A distance L apart, of a material having thermal conductivity k are at temperature t1 and t2 then heat flow rate through it will be

a) ( t1 – t2) b) ( t1 – t2) C) ( t1 – t2) D) ( t1 – t2) e) ( t1 – t2)

85.The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as

a) Kirchhoff’s law b) Stefan ‘s law c) Wien’ law d) Planck’s law e) Black body law

86. According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to

a) Absolute temperature b) T 2 C) T 3 D) T4 E) 1/ T

87. According to Planck’s law, the wavelength corresponding to the maximum energy is proportional to

a) Absolute temperature ( T) b) T2 c) T 3 d) T4 e) 1/ T

88. According to Wien’s law the wavelength corresponding to maximum energy is proporation to

a) absolute temperature ( T) b) T2 c) T 3 d) T4 E) 1/ T

89. Depending on the radiating properties, a body will be white when

a) = 0 , = 0 and = 1 (b) = 1 , = 0 and = 0 c) = 0 , = 1 and = 0

d) = 0 , + = 1 e) = 0 , + = 1

90.Depending on the radiating properties, a body will be black when

a) = 1 b) c) = 0

d) = 1 e) = 0, = 1

where

91. Depending on the radiating properties, a body will be opaque when

a) 1 b) 0 c) 0

d) 1 e) 0 = 1

where

92. The heat transfer equation 2 t/ x2 + 2t/ + / = 0 is known as

a) Laplace’s equation b) Stefan- Boltzmann equation c) Fourier equation

d) Poisson’s equation e) General equation of heat transfer.

93. If the inner and outer surfaces of a hollow cylinder ( having radii r1 and r2 and length L) are at temperatures t1 and t2 then rate of radial heat flow will be

**a) **** **** b)**** **** c) **** **** **

**d) ****e) 2****LK **** **

94. Two plane slabs of equal areas and conductivities in the ratio 1 : 2 are held together and temperature in between surface ends are t1 and t2 . If junction temperature in between two surface is desired to be t1+ t2/ 2 , then their thickness should be in the ratio of

a) 1 : 2 b) 2 : 1 c) 1 : 1 d) 3 : 1 e) 1 : 3

95. The heat flow rate through parallel walls of thickness L1, L2 and L3 and having surface areas A1, A2 and A3 , thermal conductivities K1 , K2 and K3, respectively and first and last walls maintained at temperature t1 and t2 will be

a) b) C)

D) E)

96. If the inner and outer walls of a hollow sphere having surface areas of A1 and A2 and inner outer radii r1 and r2, are maintained at temperature t1 and t2 , then rate of heat flow will be

a) K A1 A2 b) K /

c) 4k t1-t2 / d) 4k r1r2 t1-t2 /

e) none of the above

97. At thermal equilibrium

a) absorptivity is greater than emissivity b) absorptivity is lesser than emissivity

c) absorptivity is equal to emissivity d) sum of absorptivity and emissivity is unity

e) None of the above

98. The ratio of emissive power of a body to the emissive power of a perfectly black body is called

a) absorptivity b) emissivity c) diffusivity

d) conductivity e) absorptive power

99. The wave length of the radiation emitted

.

a) depends on temperature only b) depends on ( temperature ) 2

c) does not depend on material of body d) depends on material of body

e) (a) and ( c) above

100.Fig. 6.1 shows the variation of temperature acoress the thickness of material with different thermal conductivities under steady states. Curve C will be applicable when thermal conductibvity of the material

a) increase with increase in temperature

b) decrease with increase in temperature

c) is very large

d) none of the above

thickness

FIG. 6.1

### ANSWER KEY MECH TEST – 1

1. B 2. E 3. B 4. B 5. C

6. A 7. C 8. C 9.B 10. B

11. B 12. D 13. C 14. C 15. A

16. E 17. D 18. D 19. D 20. D

21. D 22. B 23. C 24. A 25. D

26. E 27. D 28. E 29. E 30.B

31. E 32.D 33. A 34. D 35. E

36. C 37. C 38.D 39. D 40 .A

41.A 42. C 43.D 44. C 45.B

46.D 47.A 48.C 49.D 50.B

51. C 52. A 53.C 54. E 55.A

56. A 57. D 58. B 59.A 60. D

61.A 62. E 63. D 64.D 65.D

66. C 67. E 68. D 69.C 70.A

71. C 72. B 73.A 74.D 75.C

76.C 77.D 78.B 79.C 80.A

81. C 82. A 83. D 84. A 85. A

91. D 92. A 93.E 94.A 95.A

96.A 97.C 98.B 99. E 100. C

86. D 87. E 88. A 89. B 90.A

1. D 92. A 93.E 94.A 95.A

96.A 97.C 98.B 99. E 100. C

### TEST-4 (MECHANICAL)

Q.1 When a body is subjected to a direct tensile stress () in one plane, then maximum normal stress occurs at a section inclined at……………….. to the normal of the section.

a) 00 b) 300

c) 450 d) 900

Q.2 When a body is subjected to a direct tensile stress (), the maximum normal stress is equitation the direct tensile stress.

a) Agree b) Disagree

Q.3 A body is subjected to a direct tensile stress 9) in one plane. The shear stress is maximum a section inclined at……. To thermal of the section.

a) 450 & 900 b) 450 & 1350

c) 600 & 1500 d) 300 & 350

Q.4 Principle plane is a plane on which the shear stress is

a) zero b) minimum

c) maximum

Q.5 A body is subjected to a direct tensile stress of 300 MPa in one plane accompanied by a simple shear stress of 200 MPa. The maximum normal stress will be

a) -100 MPa b) 250MPa

c) 300MPa d) 400MPa

Q.6 For the above question, the minimum normal stress will be

a) -100 MPa b) 250MPa

c) 300MPa d) 400MPa

Q.7 For questions NO. 89, the maximum shear stress will be

a) -100MPa b) 250MPa

c) 300MPa d) 400MPa

Q.8 A body is subjected to a tensile stress of 1200 MPa on one plane and another tensile stress of MPa on a plane at right angles to the former. It is also subjected to a shear stress of 400MPa on she same planes. The maximum normal stress will be

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.9 For the above questions, the minimum normal stress will be.

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.10 For question No. 95, the maximum shear stress will be

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.11 A body is subjected to two normal stresses 20kN/m2 (tensile) and 10kN/m2 (compressive) perpendicular to each other. The maximum shear stress is

a) 5kN/m2 b) 10kN/m2

c ) 15kN/m2 d) 20kN/m2

Q.12 For biaxial stress, the planes of maximum shear are at right angles to each other and are inclined 4500 to the principal planes.

a) True b) False

Q.13 The maximum shear stress is……. The algebraic difference of maximum and minimum normal stresses.

a) equal to b) one-fourth

c) one-half d) twice

Q.14 In Fig. 2.40, the tangential stress is given by

a) OC b) OP

c) OQ d) PQ

Q.15 In Fig. 2.40, the resultant stress is given by

a) OC b) OP

c) OQ d) PQ

Q.16 The radius o the Mohr’s circle in.

a) sum of two principal stresses

b) difference of two principal stresses

c) half the sum of two principal stresses

d) half the difference of two principal stresses

Q.17 The maximum shear stress, in Fig. 2.40, is equal to ………. of the Mohr’s circle.

a) radius b) diameter

c) circumference d) area

Q.18 Mohr’s circle is used to determine the stresses on an oblique section of a body subjected

a) direct tensile stress in one plane accompanied by a shear stress

b) direct tensile stress in two mutually perpendicular directions

c) direct tensile stress in two mutually perpendicular directions accompanied by a simple shear stress

d) all of the above

Q.19 The extremities of any diameter on Mohr’s circle represent

a) principal stresses

b) normal stresses on planes at 450

c) shear stresses on planes at 450

d) normal and shear stresses on a plane

Q.20 The maximum shear stress is equal to the radius of Mohr’s circle.

a) Correct b)Incorrect

Q.21 The energy stored in a body when strained within elastic limit is known as

a) resilience b) proof resilience

c) strain energy d) impact energy

Q.22 The total strain energy stored in a body termed as

a) resilience

b) proof resilience

c) impact energy

d) modulus of resilience

Q.23 The proof resilience is the maximum strain energy which can be stored in a body.

a) Yes b) No

Q.24 The proof resilience per unit volume of a material is known as modulus of resilience.

a) True b) False

Q.25 Strain energy is the

a) energy stored in a body when strained within elastic limits

b) energy stored in a body when strained upto the breaking of a specimen

c) maximum strain energy which can be stored in a body

d) proof resilience per unit volume of material

Q.26 The strain energy stored in a body, when suddenly loaded, is……. The strain energy stored when same load is applied gradually.

a) equal to b) one-half

c) twice d) four times

Q.27 Resilience is the

a) energy stored in a body when strained within elastic limits

b) energy stored in a body when strained up to the breaking of the specimen

c) maximum strain energy which can be stored in a body.

d) None of the above

Q.28 The total strain energy stored in a body is called proof resilience.

a) Agree b) Disagree

Q.29 Modulus of resilience is the proof resilience per unit volume of a material.

a) Correct b) Incorrect

Q.30 The stress induced in a body, when suddenly loaded, is………….. the stress induced when the same load is applied gradually.

a) equal to b) one-half

c) twice d) four times

Q.31 The strain energy stored in a spring, when subjected to maximum load, without suffering permanent distortion, is known as

a) impact energy

b) proof resilience

c) proof stress

d) modulus of resilience

Q.32 The capacity of a strained body for doing work on to removal of the straining force, is called

a) Strain energy b) resilience

c) Proof resilience d) impact energy

Q.33 Which of the following statement is correct?

a) The energy stored in a body, when strained within elastic limit is known as strain energy.

b) The maximum strain energy which can be stored in a body is termed as proof resilience.

c) The proof resilience per unit volume of material is known as modulus of resilience

d) all of the above

Q.34 A beam which is fixed at one end and free at the other is called

a) Simply supported beam

b) Fixed beam

c) Overhanging beam d) cantilever beam

Q.35 A beam supported at its both ends is not a simply supported beam.

a) True b) False

Q.36 A beam extending beyond the supports is called

a) Simply supported beam

b) Fixed beam

b) Fixed beam

c) Overhanging beam

d) Cantilever beam

Q.37 A beam encastered at both the ends is called

a) Simply supported beam

b) Fixed beam

c) Cantilever beam

d) Continuous beam

Q.38 A beam supported on more than two supports is called

a) Simply supported beam

b) Fixed beam

c) Overhanging beam

d) Continuous beam

Q.39 A cantilever beam is one which is

a) Fixes at both ends

b) Fixed at one end free at the other end

c) Supported at its ends

d) Supported on more than two supports

Q.40 A simply supported beam is one which is supported on more than two supports.

a) True b) False

Q.41 An overhanging beam must overhang on both sides.

a) Right b) Wrong

Q.42 A fixed beam is one which is fixes at………. of its ends.

a) one b) both

Q.43 A continuous beam is one which is

a) Fixed at both ends

b) Fixed at one end free at the other end

c) Supported on more than two supports

d) extending beyond the supports

Q.44 A concentrated load is one which

a) acts at a point on a beam

b) Spreads non-uniformly over the whole length of a beam

c) Spreads uniformly over the whole length of a beam

d) Varies uniformly over the whole length of a beam

Q.45 A load which acts at a point on a beam is not called uniformly distributed load.

a) Agree b) Disagree

Q.46 A uniformly distributed load may be assumed to behave like a point load at the centre of gravity load for all sorts of calculations.

a) Right b) Wrong

Q.47 A load which is spread over a beam in such a manner that it varies uniformly over the whole length of a beam is called uniformly ………. Load.

a) Distributed b) varying

Q.48 The shear fore at a point on a beam is the algebraic……………. of all the forces on either side of the point.

a) sum b) difference

Q.49 The bending moment at a point on a beam the algebraic…………… of the moments on either of the point.

a) sum b) difference

Q.50 The bending moment on a section is maximum where shear force is

a) Minimum b) maximum

c) Changing sign d) zero

29-01-2016

### TEST-3 (MECHANICAL)

Q.1 When a body is subjected to a direct tensile stress () in one plane, then maximum normal stress occurs at a section inclined at……………….. to the normal of the section.

a) 00 b) 300

c) 450 d) 900

Q.2 When a body is subjected to a direct tensile stress (), the maximum normal stress is equitation the direct tensile stress.

a) Agree b) Disagree

Q.3 A body is subjected to a direct tensile stress 9) in one plane. The shear stress is maximum a section inclined at……. To thermal of the section.

a) 450 & 900 b) 450 & 1350

c) 600 & 1500 d) 300 & 350

Q.4 Principle plane is a plane on which the shear stress is

a) zero b) minimum

c) maximum

Q.5 A body is subjected to a direct tensile stress of 300 MPa in one plane accompanied by a simple shear stress of 200 MPa. The maximum normal stress will be

a) -100 MPa b) 250MPa

c) 300MPa d) 400MPa

Q.6 For the above question, the minimum normal stress will be

a) -100 MPa b) 250MPa

c) 300MPa d) 400MPa

Q.7 For questions NO. 89, the maximum shear stress will be

a) -100MPa b) 250MPa

c) 300MPa d) 400MPa

Q.8 A body is subjected to a tensile stress of 1200 MPa on one plane and another tensile stress of MPa on a plane at right angles to the former. It is also subjected to a shear stress of 400MPa on she same planes. The maximum normal stress will be

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.9 For the above questions, the minimum normal stress will be.

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.10 For question No. 95, the maximum shear stress will be

a) 400MPa b) 500MPa

c) 900MPa d) 1400MPa

Q.11 A body is subjected to two normal stresses 20kN/m2 (tensile) and 10kN/m2 (compressive) perpendicular to each other. The maximum shear stress is

a) 5kN/m2 b) 10kN/m2

c ) 15kN/m2 d) 20kN/m2

Q.12 For biaxial stress, the planes of maximum shear are at right angles to each other and are inclined 4500 to the principal planes.

a) True b) False

Q.13 The maximum shear stress is……. The algebraic difference of maximum and minimum normal stresses.

a) equal to b) one-fourth

c) one-half d) twice

Q.14 In Fig. 2.40, the tangential stress is given by

a) OC b) OP

c) OQ d) PQ

Q.15 In Fig. 2.40, the resultant stress is given by

a) OC b) OP

c) OQ d) PQ

Q.16 The radius o the Mohr’s circle in.

a) sum of two principal stresses

b) difference of two principal stresses

c) half the sum of two principal stresses

d) half the difference of two principal stresses

Q.17 The maximum shear stress, in Fig. 2.40, is equal to ………. of the Mohr’s circle.

a) radius b) diameter

c) circumference d) area

Q.18 Mohr’s circle is used to determine the stresses on an oblique section of a body subjected

a) direct tensile stress in one plane accompanied by a shear stress

b) direct tensile stress in two mutually perpendicular directions

c) direct tensile stress in two mutually perpendicular directions accompanied by a simple shear stress

d) all of the above

Q.19 The extremities of any diameter on Mohr’s circle represent

a) principal stresses

b) normal stresses on planes at 450

c) shear stresses on planes at 450

d) normal and shear stresses on a plane

Q.20 The maximum shear stress is equal to the radius of Mohr’s circle.

a) Correct b)Incorrect

Q.21 The energy stored in a body when strained within elastic limit is known as

a) resilience b) proof resilience

c) strain energy d) impact energy

Q.22 The total strain energy stored in a body termed as

a) resilience

b) proof resilience

c) impact energy

d) modulus of resilience

Q.23 The proof resilience is the maximum strain energy which can be stored in a body.

a) Yes b) No

Q.24 The proof resilience per unit volume of a material is known as modulus of resilience.

a) True b) False

Q.25 Strain energy is the

a) energy stored in a body when strained within elastic limits

b) energy stored in a body when strained upto the breaking of a specimen

c) maximum strain energy which can be stored in a body

d) proof resilience per unit volume of material

Q.26 The strain energy stored in a body, when suddenly loaded, is……. The strain energy stored when same load is applied gradually.

a) equal to b) one-half

c) twice d) four times

Q.27 Resilience is the

a) energy stored in a body when strained within elastic limits

b) energy stored in a body when strained up to the breaking of the specimen

c) maximum strain energy which can be stored in a body.

d) None of the above

Q.28 The total strain energy stored in a body is called proof resilience.

a) Agree b) Disagree

Q.29 Modulus of resilience is the proof resilience per unit volume of a material.

a) Correct b) Incorrect

Q.30 The stress induced in a body, when suddenly loaded, is………….. the stress induced when the same load is applied gradually.

a) equal to b) one-half

c) twice d) four times

Q.31 The strain energy stored in a spring, when subjected to maximum load, without suffering permanent distortion, is known as

a) impact energy

b) proof resilience

c) proof stress

d) modulus of resilience

Q.32 The capacity of a strained body for doing work on to removal of the straining force, is called

a) Strain energy b) resilience

c) Proof resilience d) impact energy

Q.33 Which of the following statement is correct?

a) The energy stored in a body, when strained within elastic limit is known as strain energy.

b) The maximum strain energy which can be stored in a body is termed as proof resilience.

c) The proof resilience per unit volume of material is known as modulus of resilience

d) all of the above

Q.34 A beam which is fixed at one end and free at the other is called

a) Simply supported beam

b) Fixed beam

c) Overhanging beam d) cantilever beam

Q.35 A beam supported at its both ends is not a simply supported beam.

a) True b) False

Q.36 A beam extending beyond the supports is called

a) Simply supported beam

b) Fixed beam

b) Fixed beam

c) Overhanging beam

d) Cantilever beam

Q.37 A beam encastered at both the ends is called

a) Simply supported beam

b) Fixed beam

c) Cantilever beam

d) Continuous beam

Q.38 A beam supported on more than two supports is called

a) Simply supported beam

b) Fixed beam

c) Overhanging beam

d) Continuous beam

Q.39 A cantilever beam is one which is

a) Fixes at both ends

b) Fixed at one end free at the other end

c) Supported at its ends

d) Supported on more than two supports

Q.40 A simply supported beam is one which is supported on more than two supports.

a) True b) False

Q.41 An overhanging beam must overhang on both sides.

a) Right b) Wrong

Q.42 A fixed beam is one which is fixes at………. of its ends.

a) one b) both

Q.43 A continuous beam is one which is

a) Fixed at both ends

b) Fixed at one end free at the other end

c) Supported on more than two supports

d) extending beyond the supports

Q.44 A concentrated load is one which

a) acts at a point on a beam

b) Spreads non-uniformly over the whole length of a beam

c) Spreads uniformly over the whole length of a beam

d) Varies uniformly over the whole length of a beam

Q.45 A load which acts at a point on a beam is not called uniformly distributed load.

a) Agree b) Disagree

Q.46 A uniformly distributed load may be assumed to behave like a point load at the centre of gravity load for all sorts of calculations.

a) Right b) Wrong

Q.47 A load which is spread over a beam in such a manner that it varies uniformly over the whole length of a beam is called uniformly ………. Load.

a) Distributed b) varying

Q.48 The shear fore at a point on a beam is the algebraic……………. of all the forces on either side of the point.

a) sum b) difference

Q.49 The bending moment at a point on a beam the algebraic…………… of the moments on either of the point.

a) sum b) difference

Q.50 The bending moment on a section is maximum where shear force is

a) Minimum b) maximum

c) Changing sign d) zero

### TEST-2 (STRENGTH OF MATERIL)

**Objective Type Questions:-**

Q.1 The unit of S.I units is

a) N/ mm2 b) kN/ mm2

c) N/ m2 d) any one of these

Q.2 The deformation per unit length is called

a) tensile stress b) compressive stress

c) shear stress d) strain

Q.3 The unit of strain is

a) N-mn b) N/ mn

c) mm d) no unit

Q.4 Strain is equal to

a) I/ & l b) &l / l

c) l.&l d) l+&l

Q.5 When a body is subjected to two equal and opposite pushes, as a result of which of body and to reduce its length, the stress and strain induced is compressive

a) True b) False

Q.6 When a body subjected to two and opposite pulls, as a result of which of body tends extend its length, the stress and strain induced is

a) compressive stress, tensile strain

b) tensile stress, compressive strain

c) tensile stress, tensile strain

d) compressive stress, compressive strain

Q.7 When a body is subjected to two equal and opposite forces, acting tangentially across the section, as a result of which the body tends to shear off across the section, the stress and induced is

a) tensile stress, tensile strain

b) compressive stress, compressive strain

c) shear stress, tensile strain

d) shear stress, shear strain

Q.8 Which of the following is a proper sequence?

a) proportional limit, elastic limit, yielding, failure

b) elastic limit, proportional limit, yielding failure

c) yielding, proportional limit, elastic , limit, failure

d) None of these above

Q.9 Hook’s law holds good up to

a) yield point

b) elastic limit

c) plastic limit

d) breaking point

Q.10 Whenever a material is loaded within elastic limit , stress is ………………strain.

a) equal to

b) directly proportional to

c) inversely proportional to

Q.11 The ratio of linear stress to the linear strain is called.

a) modulus of rigidly

b) modulus of elastic

c) bulk modulus

d) Poisson’s ratio

Q.12 The unit of modulus of elasticity is same as those of

a) stress, strain and pressure

b) stress, force and modulus of rigidity

c) strain, force and pressure

d) stress, pressure and modulus of rigidity

Q.13 When a change in length takes place, the strain is known as

a) linear strain

b) lateral strain

c) volumetric strain

d) shear strain

Q.14 The change in length due to a tensile or compressive force acting on a body is given by

a) b)

c) d)

Q.15 The modulus of elasticity for mild steel is approximately equal to

a) 10kN/mm2 b) 80kN/mm2

c) 100kN/mm2 d) 210kN/mm2

Q.16 Young’s modulus may be defined as the ratio of

a) linear stress to lateral strain

b) lateral strain to linear strain

c) linear stress to linear strain ‘

d) shear stress to shear strain

Q.17 The unit of young’s modulus is same as that of stress.

a) True b) False

Q.18 Two bars of different materials and same size are subjected to the same tensile force. If the behave unit elongation in the ratio 2 : 5 , then the ratio of modulus of elasticity of the two materials with be

a) 2 : 5 b) 5 : 2

c) 4 : 3 d) 3 : 4

Q.19 When a bar of length l and diameter d is rigidly fixed at the upper end and hanging freely, there the total elongation produced in the bar due to its own weight is

a) b)

c) d)

Q.20 The deformation of a bar under its own weight is ………………. The deformation, if the same body subjected to a direct load equal to weight of the body.

a) equal to b) half

c) double d) quadruple

Q.21 The elongation of a conical bar under its own weight is……………that of prismatic bar of the same length.

a) equal to b) half

c) one-third d) two-third

Q.22 The length of a conical bar is l, diameter of base is d and weight per unit volume is w. It is fixed at its upper end and hanging freely. The elongation of the bar under the action of its own weight will be.

a) b)

c) d)

Q.23 Strain rosettes are used to

a) measure shear strain

b)measure linear strain

c) measure volumetric strain ‘

d) relieve strain

Q.24 A bar of length L meters extends by l mm under a tensile force of P. The strain produced in the bar is.

a) l/L b) 0.1l/L

c) 0.01l/L d) 0.001l/L

Q.25 The extension of a circular bar tapering uniformly from diameter d1 at one end diameter d2 at other end, and subjected to an axial pull of P is …………. The extension of a circular bar of diameter subjected to the same load P.

a) equal to

b) less than

c) greater than

Q.26 The ultimate tensile stress for mild steel is………… the unlimited compressive stress.

a) equal to

b) less than

c) more than

Q.27 The maximum stress produced in a bar of tapering section is at

a) smaller and b) larger end c) middle d) anywhere

Q.28 Modular ratio of the two materials is the ratio of

a) linear stress to linear strain

b) shear stress t shear strain

c) their modulus of elasticity’s

d) their modulus of rigidities

Q.29 A rod is enclosed centrally in a tube and the assembly is tightened by rigid washer. If the assembly is subjected to a compressive load, than

a) rod is under compression

b) tube is under compression

c) both rod and tube are under compression

d) tube is under tension and rod is under compression

Q.30 A bolt is made to pass through a tube and both of them are tightly fitted with the help of pushers and nuts. If the nut is tightened, then

a)both and tube are under tension

b) bolt and tube are under compression

c) bolt is under compression and tube is under tension

d) bolt is under tension and tube is under compression

Q.31 When a bar is subjected to a change of temperature and its deformation is prevented, the stress in the bar is/

a) tensile stress b) compressive stress

c) shear stress d) thermal stress

Q.32 A steel bar of 5 mm is heated from 15 deg. C to 40degC. And it is free to expand. The bar will induce.

a)no stress b)shear stress

c)tensile stress d) compressive stress

Q.33 When a bar is cooled to- 5 deg. C , it will develop

a) no stress b) shear stress

c) tensile stress d) compressive stress

Q.34 A bar of copper and steel form a composite system, which is heated to a temperature of 40 deg. .The stress induced in the copper bar will be

a) tensile b) compressive

c) shear d) zero

Q.35 The thermal stress in a bar is …………. Proportional to the change in temperature.

a) directly b) indirectly

Q.36 The thermal stress……..upon the cross- sectional area of the bar.

a) depends b) does not depend

Q.37 If there is a fall in the temperature of a composite body , then a member having green coefficient of linear expansion will be subjected to compressive stress.

a) True b) False

Q.38 The thermal or temperature stress is a function of.

a) increase of temperature

b) modulus of elasticity

c) coefficient of linear expansion

d) all of these

Q.39 Which of the following statement is correct.

a) The stress is the pressure per unit area.

b) The strain is expressed in mm.

c) Hook’s law holds good up to the breaking point.

d) Stress is directly proportional to strain within elastic limit.

Q.40 The deformation of the bar per unit length in the direction of the force is known as

a) linear strain b) lateral strain

c) volumetric strain d) shear strain

Q.41 Every direct stress is always accompanied by a strain in its own direction and an opposite k of strain in every direction, at right angles to it. Such a strain is known as

a) linear strain b) lateral strain

c) volumetric strain d) shear strain

Q.42 The ratio of the lateral strain to the strain is called.

a) modulus of elasticity

b) modulus of rigidity

c) bulk modulus

d) Poisson’s ratio

Q.43 Poisson’s ratio is the ratio of linear strain to the volumetric strain.

a) True b) False

Q.44 A steel bar 2m long, 20 mm wide and 10mm thick is subjected to a pull of 2kN . If the same is subjected to a push of 2kN, the Poisson’s ratio of the bar in the tension will be ……..the Poisson ratio for the bar in compression.

a) equal to

b) less than

c) greater than

Q.45 The Poisson’s ratio for steel vanish from

a) 0.23-0.27 b) 0.25-0.37

c) 0.31-0.34 d) -.32-0.42

### TEST-1 MECHANICAL (MECHANICS)

Objective Type Questions:-

Q.1 The term ‘force’ may be defined as an agent t which produces or tends to produce, destroys or tends to destroy motion.

a) Agree b) disagree

Q.2 A force while acting on a body my

a) change its motion

b) balance the forces, already acting on it

c) Give rise to the internal stresses in it

d) all of these

Q.3 In order determine the effects of a force, acting on a body, we must know

a) Magnitude of the force

b) line of action of the

c) Nature of the force i.e. whether the force is push or pull

d) all of the above

Q.4 The unit of force in S.I. system of units is

a) Dyne b) kilogram

c) Newton d) watt

Q.5 One kg force is equal to

a) 7.8 N b) 8.9 N

c) 9.8N d) 12N

Q.6 A resultant force is a single force which produces the same effect as produced by all the given forces acting on a body.

a) True b) False

Q.7 The process of finding out the resultant force is called……………. of forces.

a) composition b) resolution

Q.8 The algebraic sum of the resolved parts of a number of forces in a given direction is equal to she resolved part of their resultant in the same direction. This is known as

a) principal of independence of forces

b) principle of resolution of forces

c) principle of transmissibility of forces

d) none of these

Q.9 Vectors method for the resultant force is also called polygon law of forces.

a) Correct b) Incorrect

Q.10 The resultant of two force P and Q acting at an angle is.

a) (p2 + Q2 + 2PQ sin)

b) (P2+Q2+2PQ cos)

c) (P2+Q2-2PQ cos )

d) (P2+Q2-2PQ tan)

Q.11 If the resultant of two forces P and Q acting at an angle , makes an angle with the force P, then.

a)tan b) tan

c) tan d) tan

Q.12 The resultant of two forces P and Q (such that P>Q) acting along the same straight line, but opposite direction, is given by

a) P + Q b) P – Q

c) P / Q d) Q / P

Q.13 The resultant of two equal forces P making an angle , is given by

a) 2P sin /2 b) 2Pcos /2

d) 2P tan / 2 d) 2P cot /2

Q.14 The resultant of two forces each equal to P and acting at right angles is

a) P / b) P/2

c) p/ d)

Q.15 The angles between two forces when the resultant is maximum and minimum respectively are

a) 00 and 1800 b) 1800 and 00

c) 900 and 1800 d) 900 and 00

Q.16 If the resultant of two equal has the same magnitude as either of the forces, then the angle between the two forces is:

a) 300 b) 600 c) 900 d) 1200

Q.17 The resultant of the two forces P and Q is R. If Q is doubled, the new resultant is perpendicular to P. Then

a) P = Q b ) Q = R

c) Q = 2R d) None of these

Q.18 Two force at acting at an angle of 1200. The bigger force is 40N and the resultant is perpendicular to the smaller one. The smaller force is:

a) 20N b) 40N

c) 80N d) None of these

Q.19 The terms ‘leverage’ and ‘mechanical advantage’ of a compound lever have got the same meaning.

a) Right b) Wrong

Q.20 A number of forces acting at a point will be in equilibrium, if

a) all the forces are equally inclined

b) sum of the forces is zero

c) sum of resolved parts in the vertical direction is zero.

d) sum of resolved parts in the horizontal direction is zero

Q.21 If a number of forces are acting at a point, their resultant is given by

a) ()2+()2

b)

c) ()2+()2 +2()()

d)

Q.22 If a number of forces are acting at a point, their resultant will be inclined at in angle with the horizontal, such that

a) tan =

b) tan =

c) tan =

d) tan

Q.23 The triangle law of forces states that if two forces acting simultaneously on a particle, be represented in magnitude and direction by the two sides of a triangle taken in order, then their resultant may be represented in magnitude and direction by the third side of a triangle, taken in opposite order.

a) True b) False

Q.24 The polygon law of forces states that if a number of forces, acting simultaneously on a particle, be represented in magnitude and direction by the sides a polygon taken in order, then their resultant is represented in magnitude and direction by the closing side of the polygon, taken in opposite direction.

a) Correct b) Incorrect

Q.25 Concurrent forces are those forces whose lines of action.

a) lie on the same line b

b) meet at one point

c) meet on the same plane

d) none of these

Q.26 If the resultant of a number of forces acting on a body is zero, then the body will not be in equilibrium.

a) Yes b) No

Q.27 The forces, which meet at one point their lines of action also lie on the same plane, are known as.

a) coplanar concurrent forces

b) coplanar non-concurrent forces

c) non-coplanar concurrent forces

d) non-coplanar non-concurrent forces

Q.28 The forces, which do not meet at one point, but their lines of action lie on the same plane, are known as coplanar non-concurrent forces.

a) Agree b) Disagree

Q.29 The forces which meet at one point, but their lines of action………………………… on the same plane, are known as non-coplanar concurrent forces.

a) lie b) do not lie

Q.30 The forces which do not meet at one point and their lines of action do not lie on the same plane are known as

a) coplanar concurrent forces

b) coplanar non-concurrent forces

c) non-coplaner concurrent forces

d) none of these

Q.31 Coplaner non-concurrent forces are those forces which ……………………. At one point, but their lines of action lie on the same plane.

a) meet b) do not meet

Q.32 Coplanar concurrent forces are those forces which

a) meet at one point, but their lines of action do not lie on the same plane

b) do not meet at one point and their lines of action do not lie on the same plane

c) meet at one point and their lines of action also lie on the same plane

d) do not meet at one point, but their lines of action lie on the same plane.

Q.33 Non- coplanar concurrent forces are those forces which

a) meet at one point, but their lines of action do not lie on the same plane

b) do not meet at one point and their lines of action do not lie on the same plane

c) do not meet at one point but their lines of action lie on the same plane

d) none of the above

Q.34 If three coplanar forces acting on a point are in equilibrium, then each force is proportional to the sine. of the angle between the other two.

a) Right b) Wrong

Q.35 According to lami’s theorem

a) the three forces must be equal

b) the three forces must be at 1200 to each other

c) the three forces must be in equilibrium

d) if the three forces acting at a point are in equilibrium, then each force is proportional to the site of the angle between the other two

Q.36 If a given force (or a given system of force) acting on a body…………….. the position of the body, but keeps it in equilibrium, then its effect is to produce internal stress in the body.

a) change b) does not change

Q.37 If three forces acting at a point are represented in magnitude and direction by the three sides of a triangle, taken in order, then the forces are in equilibrium.

a) Yes b) No

Q.38 If a number of forces acting at a point be represented in magnitude and direction by the three sides of triangle, taken in order, then the forces are not in equilibrium.

a) Agree b) Disagree

Q.39 The moment of a force.

a) is the turning effect produced by a force, on the body, on which it acts

b) is equal to the product of force acting on the body and the perpendicular distance of a point and the line of action of the force

c) is equal to twice the area of the triangle, whose base in the line representing the force and whose vertex is the point, about which the moment is taken

d) all of the above

Q.40 If a number of coplanar forces acting at a point be in equilibrium, the sum of clockwise moments must be………………….. the sum of anticlockwise moments, about any point

a) equal to

b) less than

c) greater than

Q.41 Varingon’s theorem of moments states that if a number of coplanar forces acting on a particle are in equilibrium, then

a) their algebraic sum is zero

b) their lines of acting are at equal distances

c) the algebraic sum of their moments about any point in their plane is zero.

d) the algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.

Q.42 According to the law of moments, if a number of coplanar forces acting on a particle are in equilibrium , then

a) their algebraic sum is zero

b) their lines of action are at equal distance

c) the algebraic sum of their moments about any point in their plane is zero.

d) the algebraic sum of their moments about any point is equal to the moment of their resultant force about the same point.

Q.43 For any system of coplanar forces, the condition of equilibrium is that the

a)algebraic sum of the horizontal components of all the force should be zero

b) algebraic sum of the vertical components of all the forces should be zero

c) algebraic sum of moments of all the forces about any point should be zero.

Q.44 The forces, whose lines of action are parallel to each other and act in the same directions, are known as.

a) coplanar concurrent forces

b) coplanar non-concurrent forces

c) like parallel forces

d) unlike parallel forces

Q.45 The three forces of 100N, 200N and 300N have their lines of action parallel to each other but act in the opposite directions. These forces are known as.

a) coplanar concurrent forces

b) coplanar non-concurrent forces

c) like parallel forces

d) unlike parallel forces

Q.46 Two like parallel forces are acting at a distance of 24 mm apart and their resultant is 20N. If the line of action of the resultant is 6 mm from any given force, the two forces are.

a) 15 N and 5 N b) 20 N and 5 N

c) 15 N and 15N d) none of these

Q.47 If a body is acted upon by a number of coplanar non-concurrent forces, it may

a) Rotate about itself without moving

b) Move in any one direction rotating about itself

c) Be completely at rest

d)All of these

Q.48 A smooth cylinder lying on its convex surface remains in…………….. equilibrium.

a) stable b) unstable c) neutral

Q.49 Three forces acting on a rigid body are represented in magnitude, direction and line of action by the three sides of a triangle taken order. The forces are equivalent to a couple whose moment is equal to.

a) area of the triangle

b) twice the area of the triangle

c) half the area of the triangle

d) none of these

Q.50 The principal of transmissibility of forces states that, when a force acts upon a body, its effect is.

a) same at every point on its line of action

b) different at different points on its line of action

c) minimum, if it acts at the centre of gravity of the body

d) maximum, if it acts at the centre of gravity of the body