Q1: A cylindrical transmission shaft of length 1.5 m and diameter 100 mm is made of a linear elastic material with a shear modulus of 80 GPa. While operating at 500 rpm, the angle of twist across its length is found to be 0.5 degrees. The power transmitted by the shaft at this speed is _______kW. (Rounded off to two decimal places) Take π=3.14. (2023)
A. 238.64
B. 254.35
C. 632.25
D. 456.35
Ans: (a)
Sol:
Q2: A cylindrical rod of diameter 10 mm and length 1.0 m is fixed at one end. The other end is twisted by an angle of 10º by applying a torque. If the maximum shear strain in the rod is p x 10^{3}, then p is equal to ______ (round off to two decimal places). (2019 Set  1)
A. 0.25
B. 0.5
C. 0.8
D. 0.6
Ans: (c)
Sol:
Q3: A bar of circular cross section is clamped at ends P and Q as shown in the figure. A torsional moment T=150 Nm is applied at a distance of 100 mm from end P. The torsional reactions (T_{P}, T_{Q}) in Nm at the ends P and Q respectively are (2018 Set 2)
(a) (50,100)
(b) (75,75)
(c) (100,50)
(d) 120,30)
Ans: (c)
Sol:
Q4: A hollow circular shaft of inner radius 10 mm, outer radius 20 mm, and length 1 m is to be used as a torsional spring. If the shear modulus of the material of the shaft is 150 GPa, the torsional stiffness of the shaft (in kNm/rad) is ________ (correct to two decimal places). (2018 Set 2)
A. 12.36
B. 18.26
C. 35.34
D. 48.22
Ans: (c)
Sol:
Q5: For an Oldham coupling used between two shafts, which among the following statements are correct? (2018 Set 1)
I. Torsional load is transferred along shaft axis.
II. A velocity ratio of 1:2 between shafts is obtained without using gears.
III. Bending load is transferred transverse to shaft axis.
IV. Rotation is transferred along shaft axis.
A. I and III
B. I and IV
C. II and III
D. II and IV
Ans: (b)
Sol:
Oldham coupling is used to connect two shafts which are not on the same axis means they are not aligned to the same axis
So,
(1) Torsional load is transferred along shaft axis as both shafts are rotating member.
So, that statement is correct.
(2) A velocity ratio 1:1 between shafts is obtained using gears.
So, this statement is wrong
(3) Bending load is not transferred transverse to shaft axis as there is no transverse load.
(4) Rotation is transferred along shaft axis
So, this statement is correct
Q6: A motor driving a solid circular steel shaft transmits 40kW of power at 500 rpm. If the diameter of the shaft is 40 mm, the maximum shear stress in the shaft is ____MPa. (2017 Set  1)
A. 60.7
B. 50.5
C. 55.25
D. 51.36
Ans: (a)
Sol:
Q7: Two circular shafts made of the same material, one solid (S) and one hollow (H), have the same length and polar moment of inertia. Both are subjected to the same torque. Here, θ_{s} is the twist and τ_{s} is the maximum shear stress in the solid shaft, whereas θ_{H} is the twist and τ_{H} is the maximum shear stress in the hollow shaft. Which one of the following is TRUE? (2016 Set 3)
A. ( θ_{s} = θ_{h} and τ_{s} = τ_{H}
B. ( θ_{s} > θ_{h} and τ_{s} > τ_{H}
C. ( θ_{s} < θ_{h} and τ_{s} < τ_{H}
D. (θ_{s} = θ_{h} and τ_{s} < τ_{H}
Ans: (d)
Sol:
Angle of twist
Q8: The crosssections of two solid bars made of the same material are shown in the figure. The square crosssection has flexural (bending) rigidity I1, while the circular crosssection has flexural rigidity I2. Both sections have the same crosssectional area. The ratio I1/I2 is (2016 Set 3)
(a) 1/π
(b) 2/π
(c) π/3
(d) π/6
Ans: (c)
Sol:
Q9: A simply supported beam of length 2L is subjected to a moment M at the midpoint x = 0 as shown in the figure. The deflection in the domain o≤x≤L is given by
where E is the Young's modulus, I is the area moment of inertia and c is a constant (to be determined) (2016Set 2)
The slope at the center x = 0 is
(a) ML/(2EI)
(b) ML/(3EI)
(c) ML/(6EI)
(d) ML/(12EI)
Ans: (c)
Sol:
Equation of deflection
Q10: A rigid horizontal rod of length 2L is fixed to a circular cylinder of radius R as shown in the figure. Vertical forces of magnitude P are applied at the two ends as shown in the figure. The shear modulus for the cylinder is G and the Young's modulus is E. (2016 Set 2)
The vertical deflection at point A is
(a)
(b)
(c)
(d)
Ans: (d)
Sol:
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37 videos39 docs45 tests

1. What is torsion in mechanical engineering? 
2. Why is torsion important in mechanical engineering? 
3. What are the factors affecting torsion in shafts? 
4. How is torsional stress calculated in mechanical engineering? 
5. What are the common failure modes in torsion of shafts? 

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