Answer-
a. I have learnt -Torsional
rigidity, Breaking twist, Shear modulus.
b. The twist for breaking of a yarn is
called breaking twist. It also can be defined as the number of twists required
to break a yarn. Breaking twist depends on the diameter of fiber and it is
inversely proportional to its diameter.
That is, Tb ∞ 1/d
Where, Tb = Breaking twist,
d = diameter of fiber.