Explore topic-wise MCQs in Mechanical Engineering.

This section includes 143 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.

51.

The value of factor of safety is always __ _.

A. >1
B. <1
C. =1
D. =0
Answer» B. <1
52.

Two equal and opposite forces of magnitude 10 kN are applied at the ends of a steel wire to increase its length. The internal force in the wire will be-----KN

A. 0
B. 10
C. 20
D. 15
Answer» C. 20
53.

If an axial force of 1 kN is applied to a steel rod of 100 mm2 cross section area, the stress in it will be ___ .

A. 10mpa
B. 10gpa
C. 1mpa
D. 1gpa
Answer» B. 10gpa
54.

If an axial force of 1 kN is applied to a rod of 100 mm2 cross section area, length 5 m and the modulus of elasticity of the material is 100 GPa, the change in length of the rod will be ___ .

A. 1mm
B. 1.2mm
C. 0.5mm
D. 0.25mm
Answer» D. 0.25mm
55.

If an axial force of 1 kN is applied to a rod of 100 mm cross section area produces change in length of 1 mm over a length of 12 m, the modulus of elasticity of the material will be---------

A. 120mpa
B. 10gpa
C. 12gpa
D. 120gpa
Answer» E.
56.

The longitudinal stress developed in a rod of cross section area 50 mm2 is 100 MPa. The force acting along its axis is -------

A. 2n
B. 2.5kn
C. 5n
D. 5.5kn
Answer» E.
57.

If an axial force of 15 kN is applied to a rod of 25 mm diameter, length 300 mm, the change in length of the rod was observed to be 0.045 mm. The modulus of elasticity of the material is 200 GPa. The strain in the rod will be ____ _.

A. 1.5
B. 1.5*10-4
C. 1.33*10-3
D. 0.0455
Answer» C. 1.33*10-3
58.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces of the same magnitude. The stresses induced in the two rods will be in the ratio __ _ .

A. 1 : 2
B. 2 : 1
C. 1 : 1
D. 4 : 1
Answer» C. 1 : 1
59.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 1 : 2. The stresses induced in the two rods will be in the ratio ____ _.

A. 1:1
B. 1:2
C. 1:1
D. 4:1
Answer» D. 4:1
60.

Two rods have uniform cross section areas in the ratio 1 : 2 and are subjected to axial tensile forces with magnitudes in the ratio 2 : 1. The stresses induced in the two rods will be in the ratio ____ _.

A. 1 : 2
B. 2 : 1
C. 1 : 1
D. 4 : 1
Answer» E.
61.

The change in length of a rod of uniform cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of twice the cross section area subjected to the same force will be__ mm.

A. 1
B. 2
C. 0.5
D. 4
Answer» B. 2
62.

A strip of steel (E = 200 GPa, 0.25) has a length of 1 m, width of 200 mm and thickness of 10 mm. A line of length 1 m is drawn parallel to its length on one of its side surfaces. When the strip is subjected to an axial tensile force of 100 kN, the length of the line will be                  mm.

A. 1000
B. 1000.25
C. 999.25
D. 0.25
Answer» C. 999.25
63.

The change in length of a rod of uniform circular cross section was found to be 2 mm for some applied force. The change in length of a rod of the same material and length but of half the diameter subjected to the same force will be Mm

A. 1
B. 2
C. 0.5
D. 4
Answer» E.
64.

A stepped bar of steel consists of a pmormtion with cross section area 500 mm2 connected to a portion with cross section area 1000 2. Each portion has a length of 1 m. The modulus of elasticity of steel is 200 GPa. The maximum elongation of the bar by applying an axial tensile force at the ends without exceeding a stress of 100 MPa is    mm.

A. 0.5
B. 0.75
C. 0.1
D. 0.15
Answer» C. 0.1
65.

A steel bar ABC (E = 200 GPa) is 1 m long. For AB = 0.7 m, it has cross section P area of 500 mm2 and for BC = 0.3 m the cross section area is 400 mm2. The bar is subjected to an axial pull of 100 kN. The stress is maximum in ___ _

A. ab
B. bc
C. same throughout
D. none of these
Answer» C. same throughout
66.

For the stepped rod shown in Fig. 1.3,the in .

A. aluminum
B. copper
C. steel
D. none of these
Answer» B. copper
67.

For the stepped rod shown in Fig. 1.3, the stress is maximum in .

A. aluminum
B. copper
C. steel
D. none of these
Answer» D. none of these
68.

If the member shown in Fig. 1.1 has a square cross section of 25 mm 25 mm and E = 200 GPa, the change in length of portion CD is ------mm

A. 0.16
B. -0.16
C. 0.24
D. -0.24
Answer» C. 0.24
69.

The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of CD is mm.

A. 0.15
B. -0.15
C. 0.24
D. -0.24
Answer» B. -0.15
70.

The axial force in the portion BC of the member shown in Fig. 1.1 is kN.

A. 50
B. -50
C. 40
D. -40
Answer» E.
71.

If the member shown in Fig. 1.1 has a square cross section of 25 mm 25 mm and E = 200 GPa, the change in length of portion AB is              mm.

A. 0.24
B. -0.24
C. 0.32
D. -0.32
Answer» B. -0.24
72.

The axially loaded composite rod shown in Fig. 1.2 has a uniform cross- sectional area of 500 mm 2 . The modulii of elasticity are Est = 200 GPa, Eal = 70 GPa and Ecu = 120 GPa. The change in length of the composite rod is mm.

A. 0.95
B. -0.95
C. 0.5
D. -0.5
Answer» C. 0.5
73.

A steel tube (E= 200Gpa) has an internal diameter of 40 mm, thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the change in length of the tube will be __ _mm.

A. 0.283
B. 0.5
C. 0.85
D. 0.113
Answer» C. 0.85
74.

The axial force in the portion AB of the member shown in Fig. 1.1 is kN.

A. 50
B. -50
C. 40
D. -40
Answer» B. -50
75.

A steel tube (E = 200 GPa) has an internal diameter of 40 mm thickness 10 mm and a length of 2 m. If it is subjected to an axial pull of 80 kN, the stress in the tube will be __ _MPa.

A. 28.3
B. 50.13
C. 84.88
D. 113.18
Answer» C. 84.88
76.

A steel rod of 3m length is manufactured at 250C the temperature of this rod increases to 1250C. What is the free expansion? Take E=200Gpa, α=12*10-6/0C,diameter=12mm

A. 3.2mm
B. 2.6mm
C. 4mm
D. 3.6mm
Answer» E.
77.

A steel rod of 3m is manufactured at 250C the temperature of rod is increases to 1250C. If free expansion is 3.6mm, what is the temperature stresses produced if 1.5mm expansion is permitted?

A. 100mpa
B. 200mpa
C. 150mpa
D. 140mpa
Answer» E.
78.

A steel rod of length is manufactured at a temperature 200C and its temperature increases upto 1350C.What are thermal stresses induced? E=200Gpa,α=12*10-6/0C

A. 312mpa
B. 310mpa
C. 320mpa
D. 276mpa
Answer» E.
79.

10. A tensile material is having Young’s modulus 2.1 x105 N/mm2 and modulus of Rigidity is 0.82 x105 N/mm2. The value of Bulk Modulus is ..

A. 1.4 x105 n/mm2
B. 1.6 x105 n/mm2
C. 1.81 x105 n/mm2
D. 1.5 x105 n/mm2
Answer» C. 1.81 x105 n/mm2
80.

A bar of 30 mm diameter is subjected to an axial force 280 KN length of bar is 400 m and E= 200GPa. Determine volumetric strain if m=4.

A. 1.46x10-3
B. 9.9 x 10-4
C. 2.9 x 10-3
D. 1.48 x 10-4
Answer» C. 2.9 x 10-3
81.

A rail 20 m long is prevented from expansion at both end . If the temperature is raised by 30 0C, Stress induced in rail is.. E=200 Gpa,α =12x10-6/°C

A. 24 mpa
B. 48mpa
C. 72mpa
D. 94mpa
Answer» D. 94mpa
82.

A material has modulus of rigidity equal to 0.4x105 N/mm2 and Bulk modulus equal to 0.95 x105 N/mm2 The Young’s modulus value in GPa is..

A. 115
B. 105
C. 145
D. 175
Answer» C. 145
83.

The modulus of elasticity in terms of bulk modulus and modulus of rigidity is given by

A. 9kg/(3k+g)
B. 9kg/(k+3g)
C. (3k+g)/9kg
D. (k+3g)/9kg
Answer» B. 9kg/(k+3g)
84.

For a Poisson's ratio of 0.4 for a material the ratio of shear modulus of elasticity to modulus of rigidity is

A. 14/5
B. 5/7
C. 7/5
D. 5/14
Answer» E.
85.

The ratio of Young's modulus and bulk modulus is given by

A. 3/(1+2γ)
B. 3(1+2γ)
C. 3/(1-2γ)
D. 3(1-2γ)
Answer» E.
86.

The modulus of elasticity in terms of bulk modulus is given by

A. 3k/(1+2γ)
B. 3k(1+2γ)
C. 3k/(1-2γ)
D. 3k(1-2γ)
Answer» E.
87.

The modulus of rigidity in terms of modulus of elasticity is given by

A. e/2(1-γ)
B. e/2(1+γ)
C. 2e/(1-γ)
D. 2e/(1+γ)
Answer» C. 2e/(1-γ)
88.

If ES = 3 EA , the stress in steel of a composite bar made of aluminium and steel strips each having a cross sectional area of 300 mm2 and subjected to an axial load of 12 kN

A. 10mpa
B. 20mpa
C. 30mpa
D. 40mpa
Answer» D. 40mpa
89.

Four wires of same material are applied the same load. In which of the following cases, the elongation will be maximum (length, diameter)?

A. 2m, 1mm
B. 4m, 2mm
C. 8m, 4mm
D. 12m, 6mm
Answer» B. 4m, 2mm
90.

If a bar of length L m extends by l mm under load W, the strain is

A. 1000 l/l
B. l/l
C. 0.001 l/l
D. none of the above
Answer» D. none of the above
91.

The elongation of circular tapered rod is given by…………. Where P=axial pull and d1, d2= diameters at two ends.

A. 4pl/Ï€ed1d2
B. 2pl/Ï€ed1d2
C. 4pl/ed1d2
D. 4p2l/ed1d2
Answer» B. 2pl/Ï€ed1d2
92.

Total elongation produced in a bar due to its self weight is given by……….. Where ρ is the density of material in kg/m3

A. 9.81ρl2/e
B. 9.81ρl2/2e
C. 9.81ρl/e
D. 9.81ρ2l/2e
Answer» C. 9.81ρl/e
93.

The tensile force at a distance y from support in a vertical hanging bar of length L whch carries a load P at the bottom is equal to---- where w = weight per unit length

A. p
B. p+wl
C. p+w(l-y)
D. p+wy
Answer» D. p+wy
94.

the extension per unit length of the rod due to suddenly applied load as compare to same load gradually applied to same rod is

A. same
B. double
C. three times
D. half
Answer» C. three times
95.

If L be the length and D be the diameter of cylindrical rod, then volumetric strain of the rod is equal to

A. strain of length plus strain of diameter
B. strain of diameter
C. strain of length plus twice the strain of diameter
D. strain of length
Answer» D. strain of length
96.

If D is the diameter of the sphere, then volumetric strain is equal to

A. two times the strain of diameter
B. 1.5 times the strain of diameter
C. three times the strain of diameter
D. the strain of diameter
Answer» D. the strain of diameter
97.

A metal plate of length L and width b has a circle drawn on it. If it is subjected to a compressive stress acting along its width, the circle will

A. remain circle of same radius
B. become ellipse with major axis along its width
C. become ellipse with major axis along its length
D. become circle of smaller radius
Answer» D. become circle of smaller radius
98.

If 1 is subtracted from the ratio of yield stress to working stress the quantity obtained is known as

A. margin of safety
B. f.o.s.
C. modulus of elasticity
D. none of the above
Answer» B. f.o.s.
99.

If the working load is one third of the ultimate load, the factor of safety is

A. 0.333
B. 3
C. 2
D. 1
Answer» C. 2
100.

The modulus of elasticity of a material is 210 GPa and its Poisson's ratio is 0.4. The modulus of rigidity of the material is

A. 210
B. 75
C. 350
D. 300
Answer» C. 350