Pressure Flashcards

All 7 cards in this deck

What is a fluid?

A liquid or a gas.

Which equation links pressure ($p$), force normal to a surface ($F$) and area ($A$)?

$p = \dfrac{F}{A}$

In the equation $p = \dfrac{F}{A}$, what are the units of $p$, $F$ and $A$?

$p$ in pascals (Pa), $F$ in newtons (N), $A$ in metres squared (m$^2$).

In which direction does the pressure in a fluid exert a force on a surface?

Normal (at right angles) to the surface.

How many cm$^2$ are there in 1 m$^2$?

$10\,000$ — so divide an area in cm$^2$ by $10\,000$ to get m$^2$.

What are the steps to calculate the area of a surface from the force normal to it and the pressure, giving the answer in standard form?

e.g. force $= 60$ N, pressure $= 120\,000$ Pa

1. Write the equation: $p = \dfrac{F}{A}$
2. Rearrange: $A = \dfrac{F}{p} = \dfrac{60}{120\,000}$
3. Work out and convert: $A = 0.0005 = 5 \times 10^{-4}\ \mathrm{m^2}$

True or false? Pressure is measured in newtons.

False. Pressure is measured in pascals (Pa); $1$ Pa $= 1$ N/m$^2$.