TEST 1 TO 3
(SOM)
INTRODUCTION
1. An elastic bar of length L, uniform cross sectional area A, coefficient of thermal expansion α and youngs modulus E is fixed and the two ends. The temperature of the bar is increased by T resulting in an axial stress σ. Keeping all other parameters unchanged, if the length of the bar is doubled, the axial stress would be
A) σ
B) 2 σ
C) 0.5 σ
D) 0.25ασ
Ans A
2. The creep strains are
A) Caused due to dead loads only
B) Caused due to live loads only
C) Caused due to Cyclic load
D) Independent of loads
Ans A
3. The poisons ratio is defined as
A) |Axial stress/lateral stress|
B) |lateral strain/axial strain|
C) |lateral stress/axial stress|
D) |Axial strain/lateral strain|
Ans B
4. The number of independent elastic constants for a linear elastic isotropic and homogeneous material is
A) 4
B) 3
C) 2
D) 1
Ans C
5. A mild steel specimen is under uniaxial tensile stress. Youngs modulus and yield stress for mild steel are 2x10^5MPa and 250 MPa respectively. The maximum amount of strain energy per unit volume that can be stored in this specimen without permanent set is
A) 156 Nmm/mm^3
B) 15.6 Nmm/mm^3
C) 1.56 Nmm/mm^3
D) 0.156 Nmm/mm^3
Ans D
6. For an isotropic material, the relationship between youngs modulus E, shear modulus G and poisons ratio μ is given
A) G=E/(1+μ)
B) G=E/2(1+μ)
C) G=E/(1+2μ)
D) G=E/2(1+2μ)
Ans B
7. The necessary and sufficient condition for a surface to be called as a free surface is
A) No stress should be acting on it
B) Tensile stress acting on it must be zero
C) Shear stress acting on it must be zero
D) No point on it should be under any stress
Ans C
8. The components of strain tensor at a point in the plane strain case can be obtained by measuring longitudinal strain in following directions
A) Along any two arbitrary directions
B) Along any three arbitrary directions
C) Along two mutually orthogonal directions
D) Along any arbitrary direction
Ans B
9. The summary of stress tensor at a point in the body under equilibrium is obtained from
A) Conservation of mass
B) Force equilibrium equations
C) Momentum equilibrium equations
D) Conservation of energy
Ans C
10. The shear modulus G modulus of elasticity E and the poisons ratio V of a material are related as
A) G=E/[2(1+V)
B) E=G/[2(1+V)
C) G=E/[2(1-V)
D) G=E/[2(1-V)
Ans A
11. In a linear elastic structural element
A) Stiffness is directly proportional to flexibility
B) Stiffness is inversely proportional to flexibility
C) Stiffness is equal to flexibility
D) Stiffness and flexibility are not related
Ans B
12. A cantilever beam of tubular section consists of 2 materials, copper as outer cylinder and steel as inner cylinder. It is subjected to a temperature rise of 20degree celcius and alfa copper is greater than alfa steel. The stress developed in the tubes will be
A) Compression in steel and tension in copper
B) tension in steel and compression in copper
C) no stress in both
D) tension in both the materials
Ans C
13. the maximum value of poisons ratio for an elastic material is
A) 0.25
B) 0.5
C) 0.75
D) 1.0
Ans B
14. The principal of superposition is made use of in structural computations when
A) The geometry of the structure changes by a finite amount during the application of the loads
B) The changes in the geometry of the structure during the application of the loads is too small and the strains in the structure are directly proportional to the corresponding stresses
C) The strain in the structure are not directly proportional to the corresponding stresses even though the effect of changes in geometry can be neglected
D) None of the above conditions are met
Ans B
15. A vertical rod PQ of length L is fixed at its top end P and has a flange fixed to the bottom end Q. A weight W is dropped vertically from a height h(<L) on to the flange. The axial stress in the rod can be reduced by
A) Increasing the length of the rod
B) Decreasing the length of the rod
C) Decreasing the area of cross section of the rod
D) Increasing the modulus of elasticity of the material
Ans A
TEST 4(SOM)SF AND BM
1. A simply supported beam is subjected to a uniform distributed load. Which one of the following statements is true
A) Maximum or minimum shear force occurs where the curvature is zero
B) Maximum or minimum shear force occurs where the curvature is zero
C) Maximum and minimum bending occurs where the curvature is zero
D) Maximum bending moment and maximum shear force occurs at the same section
Ans B
2. The following statements are related to bending of beams
I The slope of the bending moment diagram is equal to the shear force
II The slope of the shear force diagram is equal to the load intensity
III The slope of the curvature is equal to the flexural rotation
IV The second derivative of the deflection is equal to the curvature
The only FALSE statement is
A) I
B) II
C) III
D) IV
Ans C
3. Two people weighting W each are sitting on a plank of length L floating on water at L/4 from either end. Neglecting the weight of the plank the bending moment at the center of the plank is
A) WL/8
B) WL/16
C) WL/32
D) Zero
Ans D
4. A cantilever beam curved in plan and subjected to latera loads will develop at any section
A) Bending moment and shearing force
B) Bending moment and twisting moment
C) Twisting moment and shearing force
D) Bending moment, twisting moment and shearing force
Ans D
5. A two span continuous beam having equal spans each of length L is subjected to a uniformly distributes load W per unit length. A beam has constant flexural rigidity. The reaction at the middle support is
A) WL
B) 5WL/2
C) 5WL/4
D) 5WL/8
Ans c
6. A two span continuous beam having equal spans each of length L is subjected to a uniformly distributes load W per unit length. A beam has constant flexural rigidity. The reaction at the middle support is 5WL/4. The bending at the middle support is
A) WL^2 /4
B) WL^2 /8
C) WL^2 /12
D) WL^/16
Ans B