Strength of Materials - Bending and Shear Stress in Beam and Torsion
Exam Duration: 45 Mins Total Questions : 25
Moment of inertia of a semi-circle about its XX-axis is given by
- (a)
0.22 r3
- (b)
0.11 r4
- (c)
0.2 r4
- (d)
0.14 r4
The strength of the beam mainly depends on
- (a)
bending moment
- (b)
CG of the section
- (c)
section modulus
- (d)
All of these
If the bending moment is consistent there will be no stresses.
- (a)
compressive
- (b)
tensile
- (c)
shearing
- (d)
All of these
In the case of an I-section beam, maximum shear stress is at
- (a)
top of flange
- (b)
junction of flange and web
- (c)
middle of web
- (d)
None of the above
A shaft is subjected to torsion as shown in figure.
Which of the following figures represent the shear stress on the element LMNOPQRS?
- (a)
- (b)
- (c)
- (d)
The strength of a hollow shaft for the same length, material and weight is __________ a solid shaft.
- (a)
more than
- (b)
less than
- (c)
equal to
- (d)
None of these
In case of a circular section, the maximum shear stress is _______ per cent more than the mean shear stress
- (a)
20
- (b)
10
- (c)
66
- (d)
33
By pure bending of a beam, we meant that
- (a)
shear force in the beam is uniform throughout
- (b)
bending moment in the beam is uniform throughout
- (c)
bending moment in beam is zero
- (d)
shear force in beam is zero
Neutral axis of a beam is the axis at which
- (a)
the shear force is zero
- (b)
the moment of inertia is zero
- (c)
the bending stress is maximum
- (d)
the bending stress is zero
When a beam is loaded transversally the maximum compressive stress shall develop at
- (a)
the bottom fibres
- (b)
the neutral axis
- (c)
the top fibres
- (d)
None of these
For two shafts connected in series, find which statements is true
- (a)
torque in each shaft is the same
- (b)
shear stress in each shaft is the same
- (c)
torsional stiffness of each shaft is same
- (d)
angle of twist of each shaft is same
A solid shaft of diameter d is replaced by a hollow shaft of the same material and length and having outside diameter \(\frac{2}{\sqrt{3}}d\) and inside \(\frac{1}{\sqrt{3}}d\) . The weight of the hollow shaft will be-the weight of solid shaft
- (a)
\(\frac{2}{3}\)
- (b)
\(\frac{5}{3}\)
- (c)
twice
- (d)
same as
If shafts are connected in parallel, then which option will be true?
- (a)
torque in each shaft is the same
- (b)
shear stress in each shaft is the same
- (c)
torsional stiffness of each shaft is same
- (d)
angle of twist of each shaft is same
A beam is in triangular section with a hole of 20 mm diameter
Moment of inertia of this cross-section about its neutral axis is
- (a)
2.87x106 mm4
- (b)
3.74x106 mm4
- (c)
4.01x106 mm4
- (d)
1.29x106 mm4
A beam is in triangular section with a hole of 20 mm diameter
If maximum stress in beam section not to exceed 100 N/mm2, then maximum bending moment on beam is
- (a)
3.6 kN-m
- (b)
10 kN-m
- (c)
4 kN-m
- (d)
5.6 kN-m
A round steel bar 12 mm in diameter and 20 m long is simply supported at its ends. If weight of steel per unit volume is 78500 N, then maximum bending moment is
- (a)
500 N-m
- (b)
288 N-m
- (c)
1000 N-m
- (d)
444 N-m
Position of centroid of an area as shown in figure if r1=180 and r2=135 is
- (a)
\(\bar{X}=103,\bar{Y}=0\)
- (b)
\(\bar{X}=0,\bar{Y}=0\)
- (c)
\(\bar{X}=0,\bar{Y}=101\)
- (d)
\(\bar{X}=103,\bar{Y}=103\)
A cantilever 2.5 m long carries a UDL of 20 kN/m run. The breadth of the section remains constant and is equal to 100 mm. Determine the depth of the section at the middle of the length of the cantilever if stress remains the same throughout and equal to 120 MN/m2.
- (a)
70 mm
- (b)
90 mm
- (c)
85 mm
- (d)
88 mm
In the given figure, angIe of twist in each part is (G = 80 GPa = 80 x 103 MPa)
- (a)
0.003 rad
- (b)
0.005 rad
- (c)
0.006 rad
- (d)
0.001 rad
If maximum permissible shear stress is 80 MPa, then value of P is
- (a)
4.7 kN
- (b)
5.2 kN
- (c)
3.9 kN
- (d)
7.1 kN
A hollow shaft has 50 mm outside diameter and 30 mm internal diameter. An applied torque of 1.5 N-m is found to produce and angular twist of 0.4°, mesured on a length of 0.2 m the shaft. The value of the modulus of rigidity
- (a)
70 kN/m2
- (b)
90 kN/m2
- (c)
60 kN/m2
- (d)
80 kN/m2
The maximum power which could be transmitted by the shaft at 2000 rpm, if maximum allowable shearing stress is 70 MN/m2.
- (a)
300 kW
- (b)
310 kW
- (c)
313kW
- (d)
318 kW
A hollow shaft is subjected to a bending moment 30 kN-m and a torque of 40 kN-m. If tmax = 80 MN/m2 and d0 = 2di, then
- (a)
d0 = 75mm
- (b)
d0 = 100 mm
- (c)
d0 = 180 mm
- (d)
d0 = 150 mm
On the basis of given figure, select the right option.
- (a)
TAB = 3300, TBC = 2200
- (b)
TAB = 6380, TBC = 3080
- (c)
TAB = 880, TBC = 2200
- (d)
TAB = 0, TBC = 1100
On the basis of given figure, select the right option.
- (a)
θ=θAB=θBC=θCD
- (b)
θ=θAB+θBC+θCD
- (c)
θ=θAB-θBC-θCD
- (d)
θ=θAB+θBC-θCD