Question

Calculate greatest and least pressure exerted by a metal block of size $20cm\times 8cm\times 5cm$and having mass $5kg$. Take $g=10m/s^2$$12500Pa$

Answer 1

Step 1: Given data-

Mass of block is $M=5kg$

Dimensions of block $20cm\times 8cm\times \times 5cm$

Acceleration due to gravity$g=10\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s^2$}\right.$

Let minimum area is $=A_{min}=8\times 5=40c{m}^2$

Let maximum area is $=A_{max}=20\times 8=160c{m}^2$

Let minimum and maximum pressure be $P_1$and $P_2$ respectively.

Step 2: Finding maximum and minimum pressure,

$$\begin{gathered} P_1=\frac{Mg}{A_{min}},P_2=\frac{Mg}{A_{max}} \\ {P}_1=\frac{Mg}{A_{min}}=\frac{5\times 10}{40\times {10}^{-4}}=12500Pa, \\ {P}_2=\frac{Mg}{A_{max}}=\frac{5\times 10}{160\times {10}^{-4}}=3125Pa. \end{gathered}$$

Hence, minimum and maximum pressure are $3125Pa$ and $12500Pa$respectively.