TEST 5 TO 6
(SOM)
TRANSFORMATION OF STRESS AND STRAIN
1. If a small concrete cube is submerged deep in still water such a way that the pressure exerted on all faces of the cube is p, then the maximum shear stress developed inside the cube is
A) 0
B) p/2
C) p
D) 2p
Ans A
2. The major and minor principal stresses at a point are 3 MPa and -3 MPa respectively. The maximum shear stress at the point is
A) Zero
B) 3 MPa
C) 6 MPa
D) 9 MPa
Ans B
3. Consider the following statements
I on a principal plane, only normal stress acts
II on a principal plane, both normal and shear stresses act
III on a principal plane, only shear stress acts
IV isotropic state of stress is independent of frame of reference
The TRUE statements are
A) I and IV
B) II
C) II and IV
D) II and III
Ans A
4. An axially loaded bar is subjected to normal stress of 173 MPa. The shear stress in the bar is
A) 75MPa
B) 86.5MPa
C) 100MPa
D) 122.3MPa
Ans B
5. If the principal stresses in two dimensional case are -10 MPa and 20 MPa respectively, then maximum shear stress at the point is
A) 10 MPa
B) 15 MPa
C) 20 MPa
D) 30 MPa
Ans B
6. A small element at the critical section of component is in a bi axial state of stress with the two principal stresses being 360 MPa and 140 MPa. The maximum shear stress is
A) 220 MPa
B) 180 MPa
C) 314 MPa
D) 330 MPa
Ans B
7. Pick the incorrect statement from the following four statements
A) On the plane which carries maximum normal stress, the shear stress is zero
B) Principal planes are mutually orthogonal
C) On the plane which caries maximum shear stress, the normal stress is zero
D) The principal stress axes and principal strain axes coincide for an isotropic material
Ans C
8. The state of two dimensional stresses acting on a concrete lamina consists of a direct tensile stress of 1.5 N/mm^2, and shear stress of 1.20 N/mm^2, which cause cracking of concrete. Then the tensile strength of the concrete in N/mm^2 is
A) 1.50
B) 2.08
C) 2.17
D) 2.29
Ans C
9. The magnitude of the only shear stress acting at a point in plane stress situation is 7.5 N/mm^2. The magnitude of the principal stresses will be
A) + 15.0 N/mm^2 and -7.5 N/mm^2
B) + 7.5 N/mm^2 and -15.0 N/mm^2
C) + 7.5 N/mm^2 and -7.5 N/mm^2
D) + 10.0 N/mm^2 and -7.5 N/mm^2
Ans C
TEST 7(SOM)BENDING STRESS IN BEAMS
1. A cantilever beam of length 2m with a square section of side length 0.1m is loaded vertically at the free end. The vertical displacement at the free end is 5mm. The beam is made of steel with youngs modulus of elasticity of 20x10^11 N/m^2. The maximum bending stress at the fixed end of the cantilever is
A) 20.0 MPa
B) 37.5 MPa
C) 60.0 MPa
D) 75.0 MPa
Ans B
2. An 8m long simply supported elastic beam of rectangular section (100mmx200mm) is subjected to a uniformly distributed load of 10KN/m over the entire span. The maximum principal stress (in MPa up to two decimal places) at a point located at the extreme compression edge of cross section and at 2m from support is
A) 90
B) 75
C) 86
D) 100
Ans A
3. A homogeneous simply supported prismatic beam of width B depth D and span L is subjected to a concentrated load of magnitude P. The load can be placed anywhere along the span of the beam. The maximum flexural stress developed in beam is
A) 2PL/3BD^2
B) 3PL/4BD^2
C) 4PL/3BD^2
D) 3PL/2BD^2
Ans D
4. The maximum bending stress included in a steel wire of modulus of elasticity 200 KN/mm^2 and diameter 1 mm when wound on a drum of diameter 1m is approximately equal to
A) 50 KN/mm^2
B) 100 KN/mm^2
C) 200 KN/mm^2
D) 400 KN/mm^2
Ans C