Thrust and Pressure in Fluids

Vocabulary flashcards covering the concepts of thrust, pressure, liquid pressure laws, Pascal's law, and its applications in hydraulic machinery.

Thrust

The force acting normally (or perpendicular) on a surface, measured in Newtons ($N$) in S.I. units.

Pressure

The thrust per unit area of a surface, expressed by the formula $P = \frac{\text{Thrust}}{\text{Area}}$.

Pascal (Pa)

The S.I. unit of pressure, where $1\text{ pascal} = 1\,N\,m^{-2}$.

Bar

A unit of pressure where $1\text{ bar} = 10^5\,N\,m^{-2}$.

Millibar

A unit of pressure where $1\text{ millibar} = 10^{-3}\text{ bar} = 10^2\,N\,m^{-2}$.

Atmosphere (atm)

A unit of atmospheric pressure where $1\text{ atm} = 0.76\text{ m of Hg} = 1.013 \times 10^5\text{ Pa}$.

Torr

A unit of atmospheric pressure named after Torricelli, where $1\text{ torr} = 1\text{ mm of Hg}$.

Fluid

A substance which can flow, encompassing all liquids and gases.

Liquid Pressure Formula

The pressure exerted by a liquid column of density $\rho$ at a depth $h$, represented as $P = h\rho g$, where $g$ is the acceleration due to gravity.

Laws of Liquid Pressure

Five rules stating that inside a liquid, pressure increases with depth, is the same on a horizontal plane, acts in all directions, depends on liquid density, and that a liquid seeks its own level.

Pascal's Law

The principle stating that pressure exerted anywhere in a confined liquid is transmitted equally and undiminished in all directions throughout the liquid.

Hydraulic Machine Principle

The rule that a small force ($F_1$) applied on a smaller piston ($A_1$) is transmitted to produce a large force ($F_2$) on a bigger piston ($A_2$), according to $\frac{F_1}{A_1} = \frac{F_2}{A_2}$.

Hydraulic Press

A machine working on Pascal's law used for pressing cotton bales, extracting juices, or engraving monograms.

Hydraulic Jack

A device used for lifting heavy vehicles such as cars and trucks in service stations, based on the force multiplier principle of hydraulic machines.

Boyle's Law

The law mentioned in the context of rising gas bubbles, stating that the volume of a gas is inversely proportional to the pressure on it.