Which of the following statement(s) is / are true about the shear centre of a cross-section:
P: It is that point in the cross-section through which shear loads produce no twisting.
Q: This point is also the centre of twist of sections subjected to pure torsion.
$\mathrm{R}$ : The normal stress at this point is always zero.
(A) $P, Q$ and $R$
(B) P only
(C) $\mathrm{P}$ and $\mathrm{Q}$ only
(D) $\mathrm{P}$ and $\mathrm{R}$ only
Which of the following statement(s) is / are true about the shear centre of a cross-section:
P: It is that point in the cross-section through which shear loads produce no twisting.
Q: This point is also the centre of twist of sections subjected to pure torsion.
$\mathrm{R}$ : The normal stress at this point is always zero.
(A) $P, Q$ and $R$
(B) P only
(C) $\mathrm{P}$ and $\mathrm{Q}$ only
(D) $\mathrm{P}$ and $\mathrm{R}$ only