Uniaxial Direct Stress

Q. Consider the following statements:
1. In a member subjected to uniaxial tensile force the maximum normal stress is the external load divided by the maximum cross-sectional area.
2. When the structural member is subjected to uniaxial loading, the shear stress is zero on a plane where the normal stress is maximum.
3. In a member subjected to uniaxial loading, the normal stress on the planes of maximum shear stress is less than the maximum.
Which of these statements are correct?

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2 and 3

Q. A mild steel bar of square cross-section has a sectional area 200 $m{m}^2$. It is subjected to an axial force of 20 kN as shown in the below figure. The intensity of the normal tensile stress in $N/m{m}^2$ on the oblique plane 1-1 at 45° with the YY-axis which is normal to the longitudinal axis will be

1. 25
2. 50
3. 75
4. 100

Q. A mild steel bar is subjected to an axial force P, resulting in an axial stress ${\sigma }_x=100N/m{m}^2$. What would be the normal stress ${\sigma }_n$ on a plane n-n making an angle $\theta =45°$ with its axis?

1. 25 $N/m{m}^2$
2. 40 $N/m{m}^2$
3. 50 $N/m{m}^2$
4. 100 $N/m{m}^2$

Q. A bar of square cross-section, having an area of cross-section A is subjected to a compressive force P as shown in the figure.


The intensity of the tangential stress on the oblique plane is given by

1. $\frac{P}{A}sin2\theta$
2. $\frac{P}{A}cos2\theta$
3. $\frac{P}{2A}sin2\theta$
4. $\frac{P}{2A}cos2\theta$

Q. A thin rod of 10 mm diameter is subjected to a tensile force for 7850 N. What are the principal sresses and maximum shear stress?

1. 700 MPa, 50 MPa, 10 MPa
2. 100 MPa, zero, 50 MPa
3. 100 MPa, 50 MPa, 25 MPa
4. 100 MPa, zero, zero

Q. When a mild-steel specimen fails in a torsion test fracture looks like

1. 
2. 
3. 
4. 

Q.
Directions: The following items consists of two statements; one labelled as 'Assertion (A)' and the other as 'Reason (R)'.
Assertion (A): In a tension test on a cast iron specimen, the failure of the specimen is on a cross section perpendicular to the axis of the specimen.
Reason (R): The failure of the specimen is on a plane subjected to maximum tensile stress and cast iron is relatively weak in tension.

1. both A and R are true and R is the correct explanation of A
2. both A and R are true but R is not a correct explanation of A
3. A is true but R is false
4. A is false but R is true