1. Torsional stress multiplied with original cross sectional are is:
a) Maximum twisting load
b) Minimum twisting load
c) Minimum shear load
d) Yield shear load
Explanation: Torsional stress is given by the ratio of maximum twisting load and original are of cross section of the material. Therefore, torsional stress multiplied with original cross sectional gives us maximum twisting load.
2. Plastic deformation can only occur in case of torsional force.
a) True
b) False
Explanation: The above given statement is false as plastic deformation can occur in case of tensile, compressive and torsional load after a point. After this point, the body cannot recover its original shape.
3. What is the unit of polar moment of inertia?
a) m2
b) m5
c) m3
d) m4
Explanation: Polar moment of inertia denoted by J, is given by integration of radius square with respect to small area of cross-section. Hence the unit is (m)(m)(m)2 which is equal to m4.
4. In which of the following the angle of twist increases fast for a small amount of torque?
a) Cold working condition
b) Hot working condition
c) Warm working condition
d) The increase is the same for cold working, hot working and warm working
Explanation: When the torsion test is conducted in hot working, it is observed that for a slight change in torque on the given specimen the angle of twist increase fast as the material becomes soft at hot working temperature.
5. How many shear stress components can act on a 3-D object?
a) 2
b) 4
c) 5
d) 6
Explanation: On a 3-dimensional body, total 9 stress components can act, out of which 3 are normal stress components while 6 of the other are tangential or shear stress component.
6. Which type of stress is plane stress?
a) One dimensional
b) Two dimensional
c) Zero dimensional
d) Three dimensional
Explanation: Plane stress is a two-dimensional stress in which stress components on any one direction is zero. For eg. All the stress components pertaining to z component is zero.
7. Principal plane is the plane in which ___________
a) Shear stress is maximum
b) Normal stress is zero
c) Shear stress is zero
d) It doesn’t depend upon stresses
Explanation: Principle planes are those planes where the value of shear stress is equal to zero and maximum or minimum value of normal stress is present at these points
8. In a Mohr’s circle drawn on the x-y plane, which axis is the axis where normal stress is plotted?
a) X-axis
b) Y- axis
c) Z-axis
d) Normal stress isn’t related to Mohr’s circle
Explanation: In a Mohr’s circle, the x-axis or the horizontal axis in the x-y plane is the axis on which normal stress is plotted on. This axis is also called the abscissa.
9. In a Mohr’s circle drawn on the x-y plane, which axis is the axis where shear stress is plotted?
a) X-axis
b) Y- axis
c) Z-axis
d) Shear stress isn’t related to Mohr’s circle
Explanation: In a Mohr’s circle, the y-axis or the vertical axis in the x-y plane is the axis on which normal stress is plotted on. This axis is called the ordinate
10. Which of following is not a graphical method for representing stress?
a) Lame’s stress ellipsoid
b) Cauchy’s stress quadric
c) Lame’s stress circle
d) Mohr’s circle
Explanation: Lame’s stress circle cannot be used for graphical representation of stresses while Lame’s stress ellipsoid, Mohr’s circle and Cauchy’s stress quadric are used for graphically representing stress.