A rectangular block of size $10cm imes 8cm imes 5cm$ is kept in three different positions $P,Q$ and $R$ in turn as shown in the figure. In each case, the shaded area is rigidly fixed and a definite force $F$ is applied tangentially to the opposite face to deform the block. The displacement of the upper face will be

Question

A rectangular block of size $10cm 	imes 8cm 	imes 5cm$ is kept in three different positions $P,Q$ and $R$ in turn as shown in the figure. In each case, the shaded area is rigidly fixed and a definite force $F$ is applied tangentially to the opposite face to deform the block. The displacement of the upper face will be

Dr. Abubacker · Accepted Answer

(c) $\eta = \frac{F/A}{x/L} \Rightarrow x = \frac{L}{\eta} 	imes \frac{F}{A}$
If $\eta$ and $F$ are constant then $x \propto \frac{L}{A}$
For maximum displacement area at which force applied should be minimum and vertical side should be maximum, this is given in the $Q$ position of rectangular block

Explanation

Reviewed by Dr. Abubacker

Want more practice?