Question

Consider the following statements
(A) For the two shafts connected in parallel, the angle of twist of each shaft is same.
(B) For the two shafts connected in series, the shear stress in each shaft is same.
(C) The shear stress in a circular shaft under torsion varies linearly.
(D) The shear stress at the centre of a circular shaft under torsion is zero.
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (C) and (D) only
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

In torsion shear stress is directly proportional to the distance from the center of the shaft. The center experiences no shear stress.

Answer 1

The Correct Option is B

Statement A is true because when shafts are connected in parallel the angle of twist is the same for both shafts.
Statement B is false because in shafts connected in series the shear stress varies due to the varying lengths and resistances of the shafts.
Statement C is true as the shear stress in a circular shaft under torsion increases linearly with the radius from the center to the surface.
Statement D is true because the shear stress is zero at the center of a shaft under torsion increasing with radius from the center to the outer surface