$A$ wire can sustain a weight of $15 \, kg$. If it is cut into four equal parts,then each part can sustain a weight of ........ $kg$.

Why does strain have no unit?

Identify whether the following statements are True or False:
$(a)$ If a body breaks immediately after the elastic limit,then this body is known as ......
$(b)$ An elastic body which can be stretched to cause large strains is called ......

The ratio of radii of two wires of same material is $2: 1$. If these wires are stretched by equal force,the ratio of stresses produced in them is .............

The breaking stress for a wire of radius $r$ of a given material is $F \ Nm^{-2}$. The breaking stress for a wire of the same material of radius $2r$ will be:

$A$ $2 \,m$ long rod of radius $1 \,cm$ which is fixed from one end is given a twist of $0.8$ radians. The shear strain developed will be