Top 1000 Basic Level Multiple Choice Questions OF Strength of Material

         

                                                  

1. The first moment of area of a rectangular section of width b and depth h about its centre of gravity is

a) bh²/2

b) bh²/4

c) Zero

d) bh²

2.The unit of second moment of area of a rectangular section, is

a) m

b)m²

c) m³

 d) m⁴

3.The moments of inertia about X and Y axes of a planar section are I_x and I_y respectively. The polar moment of inertia of the section is,

 a) I_x+I_y

b) I_x- l_y

c) I_x.l_y

d) I_x/ l_y

4.The resultant of two forces P and Q, such that P<Q. acting along the same straight line but in pposite direction is gives by.

a) P-Q

b) Q-P

c) P/Q

d) Q/P

5. Poisson's ratio is the ratio of,

a) Lateral stress to Longitudinal stress

b) Longitudinal stress to Lateral stress

c) Lateral strain to Longitudinal strain

d) Longitudinal strain to Lateral strain

6.The unit of second moment of area of a rectangular section, is

a) The body should be at rest

b) The body should rotate at a constant angular speed

c) The resultant force acting on the body must be zero

d) The resultant force and moment acting on the body must be zero

7.The unit of angular acceleration, is

a) N-m

b) m/s2

c) rad/s

d) rad/s2

 8. If the first moment of the mass about a point is zero, then the point must be:

a) Centre of mass

b) Centre of rotation

c) Centre of acceleration

d) None of the above

9.The angular velocity (in rad/s) of a body rotating at N revolutions per minute, is

a) πN/60

b) πN/180

c) 2πN/60

d) 2πN/180

10. Which of the following is not the unit of pressure?

a) Newton

b) Kg/cm²

c) Atmosphere

d) Bar

11.For evaluation of member forces in a plane truss by Method of joints, maximum number of unknowns at a joint should be:

a) 4

b) 3

c) 2

d) 1

12. The surface area of a sphere of radius r is:

a) 2πr²

b) 4πr²

 c) 2πr³/3

d) 4πr³/3

13. D'Alembert's principle is used for

a) Reducing the problems of kinematics to equivalent statics problems

b) Stability of floating bodies

c) Designing safe structures

d) None of the above

14.The volume of a pyramid with base area B and height h is:

 a) B.h

b) B.h/2

c) B.h/3

d) B.h/4

15. body of weight W, resting on a flat horizontal surface is being pulled by a horizontal force P. If A the coefficient of friction between the body and the surface is μ.the resisting force will be:

a) μ.P

b) μ.W

c) P/μ

d) W/μ

1.What are the axioms on which behaviour of deformable member depend? a. Equilibrium of forces b. Parallelogram of forces c Mechanical properties of the material d. All of the above 2 Which of the following represents equality of cross shear correctly?

a.τ_xy = τ_yx

b.τ_xy ≠ τ_yx

c.σ_xy= σ_yx

d.σ_xy≠ σ_yx

3. Which of the following is a correct statement?

a. Planes of maximum shear stress are free from normal stresses

b. Principal planes are free from normal stresses c. Both (a) and (b) d None of the above 4.If Poisson's ratio of a material is zero, it means that

a. The material is rigid b.The material is perfectly plastic c.The longitudinal strains in the material are zero d. The longitudinal strains in the material are infinite 5.Which one of the following represents the correct lower and upper limit for Poisson's ratio(μ)?

a. 0<μ<1 b. 1<μ<1/2

c. -1/2 <μ-1/2

d. -1<μ<1

6.In the figure below the average normal stress and average shear stress on the inclined plane ABEF respectively are:

a.6.25MPA and 3.608 MPa

b.3.608 MPa and 6 25MPa c.50 MPa and 86.603MPa d.36.603 MPa and 50MPa 7.A solid cylindrical shaft of diameter 40mm is subjected to an axial force of 75KN. Determine the Normal stress due to axial load in the shaft

a.225 MP b.71.62 MP c.59.68 MPa d. 1492 MP 8.A steel rod having circular cross section is subjected to tensile load from both ends. radius of the rod gets halved due to the tensile pull and length becomes double,then the modulus of elasticity will be

a.Half of the original value b.Double of the original value c.One fourth of the original value d.Same as the original value 9.A 200 mm long cylindrical steel tube is subjected to an axial compressive load of 50KN. The inner and outer diameters of the tube are 20 mm and 30 mm respectively. The stress generated in this tube due to the axial compressive load is

a.71.56 MPa b. 94.42 MPa c. 53.05 MPa d 127.32 MPa 10.A steel rod 2m long and an aluminium rod Im long together support a rigid beam of negligible weight as shown in the figure. A load Pis hanging from the centre of the rigid beam as shown. The cross sectional area and modulus of elasticity of steel rod are 10mm² and 200 GPa and that of aluminium rod are 20 mm² and 100 GPa respectively. If the beam stays horizontal,then

a. The force exerted by the beam on both rods should be equal b. The force on aluminium rod should be twice the force on steel rod c. The force on steel rod should be twice the force on aluminium rod d.The force on steel rod should be four times the force on aluminium rod 11. A 5m long uniform steel wire, 5 mm in diameter is subjected to an axial tensile load of 5kN. A The elongation in the wire is: (E-200 GPa)

a.3.42 mm b. 7.64 mm c. 2.55 m d 6.36 mm 12.The axial strain in an aluminium rod due to an applied force is 10-³mm. If the rod is 175 mm long and 10mm in diameter, what axial stress is caused by the applied force? E=75 GPa

a.75 MPa b.75 GPa c. 30 GPa d. 90 MPa 13.Four 16 mm diameter rivets join two plates of width 100mm and thickness 10mm. The allowable stresses in bearing of the plate and shearing of rivet are 100 MPa and 50 MPa respectively. The maximum safe load P (kN) that may be applied in shearing failure of the rivet and bearing failure of the plate respectively is

a 30.4,32

b. 10.05, 16 c. 40.2, 64 d 20.1,32 14.In question 13, determine the safe load P(kN) if minimum average tensile stress in plates is 10 MPa.

a.1.2 b. 6.8 c. 10 d. 4.8 15.The state of stress(MPa) at a given point is given as following. Calculate the principal stresses in MPa.

              

a 5.44, -17.37, -33.07

b. 6.13, -18.92, -37.89 c. 1.05, 12.85 ,-24.58 d. -4.28,-18.66, 29.98

1.Which of the following statement is correct? a) The stress is pressure per unit area b) The strain is expressed in mm

c) Hooke's law holds good up to breaking point d) Stress is directly proportional to strain within elastic limit 2.A body, represented by two-dimensional plane, is subjected to a direct tensile stress of 300 MPa in one plane accompanied by a simple shear stress of 200 MPa in the same plane. The maximum shear stress will be

a)-100 MPa b) 250 MP c) 300 MP d) 400 MPa 3.Principal planes are planes having a) Maximum shear stress b) Minimum shear stress c) No shear stress d) None of the above 4.A body, represented by two-dimensional plane, is subjected to a tensile stress of 1200 MPa on one plane and another tensile stress of 600 MPa on other plane right angled to the former. The planes are also subjected to a shear stress of 400 MPa. The maximum normal stress will be

a) 400 MP

b) 500 MPa c) 900 MP d) 1400 MPa 5.The state of stress at a point in a two-dimensional loading is such that the Mohr's circle is a point located at 150 MPa on the positive normal stress axis. The maximum and minimum principal stresses, respectively, from Mohr's circle are. a) +150 MPa -150MPA b) +150 MPa, +150 MPa c) 0,-150 MPa d) 0.0 6.The state of stress at a point is given by σ_x = 100 MPa ,σ_y = -30 MPa ,σ_z = 80 MPa, τ_xy = τ_yz =τ_zx = 0.The octahedral normal stress at the point, is

a) 0 b) 25 MPa c) 50 MPa d) 100 MPa 7. The symmetry of stress tensor at a point in the body under equilibrium is obtained a) Conservation of mass b) Force equilibrium equations e) Conservation of energy d) Moment equilibrium equations 8.A body is subjected to a direct tensile stress (σ) in one plane. The shear stress is maximum at sections inclined at a) 45° and 90° b) 60° and 150°

c) 45° and 135 °

d) 30° and 135°

9.A shaft, subjected to torsion, experiences a pure shear stress on the surface. The normal stress on the surface, which is at 45° to the axis will have a value

a)τcos 45°

b) 2τcos 45° c) τcos2 45°

d) 2 τsin 45° cos 45°

10.A circular rod is subjected to an axial pull of 160 kN. If the maximum allowable shear stress on any section is 65 MPa, the required diameter of the bar should be a) 40mm b) 80mm e) 120mm d)Data is insufficient for the calculation 11.Direct normal stresses of 120MPa (tensile) and 90 MPa (compressive) act on a two-dimensional body on two mutually perpendicular planes. If major principal stress at the point is 150 MPa, the magnitude of shearing stress is a) 85 MPa b) 42 MP c) 18 MPa d) None of the above 12.The figure shows the state of stress at a certain point in a body. The magnitude of normal stresses in the x and y direction are 100 MPa and -40 MPa respectively. The radius of Mohr's stress circle representing this state of stress is:

a) 140 MPa b) 60 MPa c) 70 MPa d) 30 MPa 13.The state of stress at a point in a loaded member is shown in the figure. The magnitude of maximum shear stress and its orientations with respect to positive x axis, are:

a) 30 MPa, 0°and 90° b) 50 MPa, 26.5° and 116.5° c) 30 MPa, 26.5" and 116.5° d) 50 MPa, 0° and 90° 14.The state of stress at a point in a stressed body is given by σ_x = 18MPa ,σ_y = -50 MPa σ_z = 32 MPa, τ_xy = τ_yz =τ_zx = 0 . The octahedral shear stress and maximum shear stress, respectively, are

a) 35.8 MPa, 41 MPa

b) 29.7 MP, 34 MPa c) 23.9 MPa, 4I MPa d) 35.8 MPa, 34 MPa 15.The state of stress at a point in a loaded member is shown in the figure. The magnitude of principal stresses and their orientation with respect to positive x axis, are:

a) 84.5 MPa and - 14.5 MPa, 22.5°and 112.5° b) 145.7 MPa and -75.7 MPa, 22.5° and 112.5° c) 84.5 MPa and - 14.5 MPa, 9.2° and 99.2° d) 145.7 MPa and - 75.7 MPa, 9.2° and 99.2°