A block of wood (dimensions : $40 \text{ cm} \times 20 \text{ cm} \times 10 \text{ cm}$) is kept on a tabletop in three different positions : (a) with its side of dimensions $20 \text{ cm} \times 10 \text{ cm}$; (b) with its side of dimensions $10 \text{ cm} \times 40 \text{ cm}$; and (c) with its side of dimensions $40 \text{ cm} \times 20 \text{ cm}$. The pressure exerted by the wooden block on the tabletop in these positions is represented by $P_A$, $P_B$ and $P_C$ respectively. The pressure follows the trend
[amp_mcq option1=”$P_A > P_B > P_C$” option2=”$P_A < P_B < P_C$" option3="$P_A = P_B = P_C$" option4="$P_A < P_B = P_C$" correct="option1"]
This question was previously asked in
UPSC NDA-2 – 2023
(a) $A_A = 20 \text{ cm} \times 10 \text{ cm} = 200 \text{ cm}^2$
(b) $A_B = 10 \text{ cm} \times 40 \text{ cm} = 400 \text{ cm}^2$
(c) $A_C = 40 \text{ cm} \times 20 \text{ cm} = 800 \text{ cm}^2$
Comparing the areas: $A_A < A_B < A_C$. Since $P \propto 1/A$, the corresponding pressures will be $P_A > P_B > P_C$.