# GATE Questions & Answers of Torsion of Circular Shafts

## What is the Weightage of Torsion of Circular Shafts in GATE Exam?

Total 9 Questions have been asked from Torsion of Circular Shafts topic of Mechanics of Materials subject in previous GATE papers. Average marks 1.56.

For an Oldham coupling used between two shafts, which among the following statements are correct?
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 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 kN-m/rad) is ________ (correct to two decimal places).

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 $\left(T_P,T_Q\right)$ in Nm at the ends P and Q respectively are

The cross sections of two hollow bars made of the same material are concentric circles as shown in the figure. It is given that r3 > r1 and r4 > r2 , and that the areas of the cross-sections are the same. $J_1$ and $J_2$ are the torsional rigidities of the bars on the left and right, respectively. The ratio $J_2/J_1$ is

Consider a stepped shaft subjected to a twisting moment applied at B as shown in the figure. Assume shear modulus , G = 77 GPa. The angle of twist at C (in degrees) is _____

A hollow shaft of 1 m length is designed to transmit a power of 30 kW at 700 rpm. The maximum permissible angle of twist in the shaft is 1o. The inner diameter of the shaft is 0.7 times the outer diameter. The modulus of rigidity is 80 GPa. The outside diameter (in mm) of the shaft is _______.

A torque T is applied at the free end of a stepped rod of circular cross-sections as shown in the figure. The shear modulus of the material of the rod is G. The expression for d to produce an angular twist θ at the free end is