Question

A brick 25cm long ,9cm wide 5cm thick has a mass of 1000g determine the greatest pressure that can be exerted by the brick on a flat surface
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Answer 1

Answer:

The greatest pressure is 2178 Pa

Explanation:

Pressure

It's the force applied perpendicular to the surface of an object per unit area over which the force is distributed.

If F is the force applied and A is the surface area, the pressure is calculated as:

$\displaystyle P=\frac{F}{A}$

The brick has dimensions of 25 cm by 9 cm by 5 cm. There are three possible areas of contact:

$A_1=25*9 = 225 cm^2=0.0225\ m^2$

$A_2=25*5= 125 cm^2=0.0125\ m^2$

$A_3=9*5= 45 cm^2=0.0045\ m^2$

The  brick has a mass of m=1000 g = 1 Kg and exerts a force equal to its weight when placed on a flat surface, thus:

F = m.g = 1 * 9.8 = 9.8 N

The greatest possible pressure will occur when the area is the least possible $(0.0045\ m^2)$, since the pressure and the area are inversely proportional, thus:

$\displaystyle P_{max}=\frac{9.8}{0.0045}$

$\displaystyle P_{max}=2178 \ Pa$

The greatest pressure is 2178 Pa