The upper end of a wire of radius $4\, mm$ and length $100\, cm$ is clamped and its other end is twisted through an angle of $30^\circ$. The angle of shear is ..... $^\circ$.

The upper end of a wire of diameter $12\,mm$ and length $1\,m$ is clamped and its other end is twisted through an angle of $30^{\circ}$. The angle of shear is $........^{\circ}$.

$A$ rod of length $l$ and radius $r$ is joined to a rod of length $l/2$ and radius $r/2$ of the same material. The free end of the small rod is fixed to a rigid base,and the free end of the larger rod is given a twist of $\theta^\circ$. The twist angle at the joint will be:

$A$ rectangular metallic block of dimensions $40 \text{ mm} \times 20 \text{ mm}$ when pulled with a tension of $50 \text{ kN}$ undergoes only elastic deformation. The strain in the block is (The shear modulus of the material of the block is $40 \times 10^9 \text{ Nm}^{-2}$)

The upper end of a wire $1\,m$ long and $4\,mm$ radius is clamped. The lower end is twisted by an angle of $30^\circ$. The angle of shear is ...... $^\circ$.

$A$ steel rod is projecting out of a rigid wall. The shearing strength of steel is $345 \, MN/m^2$. The dimensions are $AB = 5 \, cm$ and $BC = BE = 2 \, cm$. The maximum load that can be put on the face $ABCD$ is .......... $kg$ (neglect bending of the rod). Take $g = 10 \, m/s^2$.