Engineering Questions with Answers - Multiple Choice Questions

# MCQs on Shear Stress and Pressure Gradient

1 - Question

What is the unit of shear stress?
a) N/m3
b) N/mm3
c) N/m
d) Pascal

d
Explanation: Shear stress is defined as the force acting per unit area. Thus, the unit of shear stress is equal to N/m2. Since, 1 Pa =1 N/m2, Pascal is the most suitable one.

2 - Question

Shear stress is caused due to _______
a) Friction
b) Temperature
c) Pressure
d) Volume

a
Explanation: Shear stress is caused due to friction between fluid particles. It is formed due to the presence of fluid viscosity. Shear stress arises from the force vector component which is parallel to the cross section.

3 - Question

Which among the following is a formula for shear stress?
a) τ = F*A
b) τ = F/A
c) τ = F/m
d) τ = F*m

b
Explanation: Shear stress is defined as the force acting per unit area. Shear stresses arise from shear components(forces), which are pairs of equal and opposite forces. These forces act on the opposite side of the object.

4 - Question

Which among the following is the correct formula to find out the shear modulus(G)?
a) E/2
b) v/2
c) E/2(1+v)
d) 2E(1+v)

c
Explanation: Shear modulus is also called as modulus of rigidity. It is defined as the ratio of shear stress to shear strain. Since Young modulus is equal to stress by strain. The most suitable option is option c. (E= Young’s Modulus, v= poison’s ratio)

5 - Question

Which among the following is an assumption of Hagen-Poiseuille equation?
a) Fluid is compressible
b) Fluid is uniform
c) Fluid is laminar
d) Fluid is turbulent

c
Explanation: Fluid flow is laminar as it is assumed to be incompressible and Newtonian. The flow is laminar through the pipe of constant cross section. Thus, there is no acceleration of fluid in the pipe. Therefore, Hagen-Poiseuille assumed that fluid flow is laminar.

6 - Question

What is the unit of pressure gradient?
a) Pa/m
b) Nm
c) Pa
d) N/m

a
Explanation: Pressure gradient is a dimensional quantity. It is expressed in units of pressure per unit length. It determines which quantity and which direction the pressure changes around a particular location.

7 - Question

Which of the following is not a basic type of stress?
a) Volumetric stress
b) Shear stress
c) Compressive stress
d) Tensile stress

a
Explanation: Volumetric stress is not a basic classification among the type of stresses as it describes the tendency of an object to deform in all directions. It deforms when the load acts uniformly in all directions.

8 - Question

What type of force does a stress produce?
b) External force
c) Internal resistive force
d) Axial force

c
Explanation: According to the continuum mechanics, stress is a physical quantity that produces internal forces. For example: When a solid bar supports a weight, each particle of the bar pushes the particles immediately below it. This happens due to the internal resistive force that is developed due to the stress on the body.

9 - Question

Hooke’s law is applicable within what limit?
a) Fracture point
b) Elastic limit
c) Ultimate strength
d) Plastic limit

b
Explanation: Hooke’s law states that force is directly proportional to its extension. Hooke’s law is applicable within the elastic limit, when the body is deformed. Example: plucking the strings of a guitar.

10 - Question

Define Factor of safety
a) Ultimate stress/Permissible stress
b) Ultimate stress/ Shear stress
c) Compressive stress/ Ultimate stress
d) Tensile stress/Shear stress