Find the pressure exerted at the tip of a drawing pin it is pushed against a board with a force of 40N?  Assume the area of the tip to be 0.1mm².

Given Force $F=40\text{N}$

Area of the tip $A=0.1{\text{mm}}^{\text{2}}=0.1\times {10}^{-6}{\text{m}}^{\text{2}}$

$\therefore$ pressure $\text{P=}\frac{\text{Force}}{\text{Area}}=\frac{F}{A}$

$\Rightarrow P\text{=}\frac{40}{0.1\times {10}^{-6}}$ $=400\times {10}^6$

$\Rightarrow P\text{=}4\times {10}^8\text{pa}$