Question

Two parallel and opposite forces each $5000N$ are applied tangentially to the upper and lower faces of a cubical metal block of side $25cm$. The angle of shear is then
(The shear modulus of the metal is $80GPa$)

• A. ${10}^{-4}rad$
• B. ${10}^{-5}rad$
• C. ${10}^{-6}rad$
• D. ${10}^{-7}rad$

Answer 1

The correct option is C ${10}^{-6}rad$

Here, $F=5000N;L=25cm=25\times {10}^{-2}m;A={(25\times {10}^{-2}m)}^2=625\times {10}^{-4}{m}^2;\eta =80GPa=80\times {10}^{9}Pa$
Angle of shear, $\theta =\frac{F}{A\eta }=\frac{5000}{625\times {10}^{-4}\times 80\times {10}^9}={10}^{-6}rad$