## October 23, 2011

### 5.4 Pressure

Recall and use the relationship between pressure, force and area:
NB: 1N/m2 = 1Pa

Using the Formula

Calculate the pressure generated by an ordinary shoe heel (person of mass 40kg, heel 5cm x 5cm), an elephant (of mass 500kg, foot of 20cm diameter) and a high-heeled shoe (person of mass 40kg, heel area 0.5cm­2). Which ones will damage a wooden floor that starts to yield at a pressure of 4000 kPa?

1. Ordinary shoe heel

2. Elephant

$A=0.5cm^{2}=0.00005m^{2}$
$p=400/0.00005$
$p=8,000,000Pa$
$p=8,000kPa$
$p=8MPa$

Clearly one can see that the high-heeled show will do the most damage to the floor.