Question

What impression does the iron cube with ribs a = 4cm make on the table? P =?

Answer 1

By the definition of the pressure, we have:

$$P=\dfrac{F}{A}=\dfrac{mg}{a^2},$$ $$P=\dfrac{\rho Vg}{a^2}=\dfrac{\rho a^3g}{a^2}=\rho ag,$$ $$P=7860\ \dfrac{kg}{m^3}\cdot 0.04\ m\cdot 9.8\ \dfrac{m}{s^2}=3081.12\ Pa.$$

Answer:

$P=3081.12\ Pa.$