Explain with an experiment to show that how strong is nylon ?

Which of the following is not am example of a polymer? protein nylon kevlar concreta

The uniform slender bar rests on a smooth horizon- tal surface when a force f is applied normal to the bar at point a. point a is observed to have an initial acceleration aa of 20 m/s2, and the bar has a corre- sponding angular acceleration of 18 rad /s2. deter- mine the distance b.

Decreased sensitivity to an unchanging stimulus is known as