Hooke's law is applicable for ....

$A$ vertical hanging bar of length $l$ and mass $m$ per unit length carries a load of mass $M$ at its lower end. Its upper end is clamped to a rigid support. The tensile stress at a distance $x$ from the support is (where $A$ is the area of cross-section of the bar):

Explain with the illustration of cranes the applications of the elastic behaviour of materials.

What is a yield point? What is a yield strength?

Check if the following statements are True or False:
$(a)$ Shear modulus of liquid is infinite.
$(b)$ For a given load (external force),steel is more deformed than rubber.
$(c)$ When a solid body is beaten,rolled,heated,or cooled,its elastic properties are affected.

$A$ wire of length $l$ and cross-sectional area $A$ is stretched by a weight $Mg$ such that its length becomes double. What is the stress in the wire?