250+ TOP MCQs on Bending Stress and Answers

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Strength of Materials Multiple Choice Questions on “Bending Stress”.

1. A beam is said to be of uniform strength, if ____________
a) B.M. is same throughout the beam
b) Shear stress is the same through the beam
c) Deflection is the same throughout the beam
d) Bending stress is the same at every section along its longitudinal axis
Answer: d
Clarification: Beam is said to be uniform strength if at every section along its longitudinal axis, the bending stress is same.

2. Stress in a beam due to simple bending is ____________
a) Directly proportional
b) Inversely proportional
c) Curvilinearly related
d) None of the mentioned
Answer: a
Clarification: The stress is directly proportional to the load and here the load is in terms of bending. So the stress is directly proportional to bending.

3. Which stress comes when there is an eccentric load applied?
a) Shear stress
b) Bending stress
c) Tensile stress
d) Thermal stress
Answer: b
Clarification: When there is an eccentric load it means that the load is at some distance from the axis. This causes compression in one side and tension on the other. This causes bending stress.

4. What is the expression of the bending equation?
a) M/I = σ/y = E/R
b) M/R = σ/y = E/I
c) M/y = σ/R = E/I
d) M/I = σ/R = E/y
Answer: a
Clarification: The bending equation is given by M/I = σ/y = E/R
where
M is the bending moment
I is the moment of inertia
y is the distance from neutral axis
E is the modulus of elasticity
R is the radius.

5. On bending of a beam, which is the layer which is neither elongated nor shortened?
a) Axis of load
b) Neutral axis
c) Center of gravity
d) None of the mentioned
Answer: b
Clarification: When a beam is in bending the layer in the direction of bending will be In compression and the other will be in tension. One side of the neutral axis will be shortened and the other will be elongated.

6. The bending stress is ____________
a) Directly proportional to the distance of layer from the neutral layer
b) Inversely proportional to the distance of layer from the neutral layer
c) Directly proportional to the neutral layer
d) Does not depend on the distance of layer from the neutral layer
Answer: a
Clarification: From the bending equation M/I = σ/y = E/R
Here stress is directly proportional to the distance of layer from the neutral layer.

7. Consider a 250mmx15mmx10mm steel bar which is free to expand is heated from 15C to 40C. what will be developed?
a) Compressive stress
b) Tensile stress
c) Shear stress
d) No stress
Answer: d
Clarification: If we resist to expand then only stress will develop. Here the bar is free to expand so there will be no stress.

8. The safe stress for a hollow steel column which carries an axial load of 2100 kN is 125 MN/m2. if the external diameter of the column is 30cm, what will be the internal diameter?
a) 25 cm
b) 26.19cm
c) 30.14 cm
d) 27.9 cm
Answer: b
Clarification: Area of the cross section of column = π/4 (0.302 – d2) m2
Area = load / stress.
So, π/4 ( 0.302 – d2) m2 = 21 / 125
d = 26.19cm.