(a)

I have learnt from the class is given below,

Tenacity, Breaking extension, Work of rupture, Initial modulus, Work factor, Work recovery, Elastic recovery, Yield stress, Yield strain, Yield point, Breaking load etc.

(b)

I have already leant all the content of Lecture.

(c)

I have understood the lecture.

 (d)

Initial modulus or stiffness: Fiber stiffness is commonly determined by the initial slope of the stress-strain curve at the origin. This is commonly known as the initial modulus; the higher initial modulus, the stiffer the fiber and the lower initial modulus, the more flexible the fiber.

Tan α ↑↓ → extension ↓↑