Pressure

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Table of Contents

Pressure ($P$) is the force exerted per unit area:

$$ \begin{equation}\begin{aligned} pressure&=\frac{force}{area}\\ P&=\frac{F}{A}\\ \end{aligned}\end{equation} $$

The SI unit is the Pascal($Pa$), equivalent to the pressure exerted by applying a one Newton ($1 N$) force over an area of one square-metre ($m^2$):

$$ \begin{equation}\begin{aligned} P&=\frac{F}{A}\\ &\rightarrow \frac{1N}{1 m^2}\\ &=1 Pa\\ \end{aligned}\end{equation} $$

Pressure in a fluid

In a fluid, pressure increases with depth. The pressure is also directly proportional to the density, $\rho$ of the fluid as well as acceleration due to gravity, $g$:

$$ \begin{equation}\begin{aligned} P=\rho gh\\ \end{aligned}\end{equation} $$
Hold a focus!

Q1: As a diver dives deeper in a body of water, he/she experiences a lesser pressure

  1. False
  2. True
  3. Pressure increases with depth and thus the diver will experience a greater pressure

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