Lecture 13: Liquids Practice Flashcards

This set of vocabulary flashcards covers key concepts from Lecture 13 regarding the properties of liquids, including pressure formulas, buoyancy principles, and surface phenomena.

Liquid

A material where molecules or atoms are packed close together but are free to move much easier than in a solid, allowing the material to change shape without being easily compressed.

Pressure ($P$)

A concept important in solids, liquids, and gases defined as the amount of force divided by the area over which it is applied, represented by the equation $P = \frac{F}{A}$.

Pascal ($Pa$)

The SI unit of pressure, equivalent to one newton divided by one meter-squared ($N/m^2$).

Liquid Pressure Equation

The pressure in a liquid is determined by the density of the liquid, gravitational acceleration, and depth, expressed as $P = \text{density} \times g \times \text{depth}$.

Buoyant Force

An upward force exerted by a liquid on an object, resulting from the difference in fluid pressure where the lowest part of the object experiences more force than the highest part.

Archimedes’ Principle

States that the buoyant force on an object is equal to the weight of the fluid it displaces, or $F_b = \text{density} \times V_{displaced} \times g$.

Buoyant Force (Weight Equation)

A secondary method to quantify the upward force on an object: the weight of the object in air minus the weight of the object in the fluid.

Principle of Flotation

States that any object that floats displaces a weight of fluid equal to its own weight.

Density Rule for Flotation

An object that is less dense than a fluid will float in it, while an object that is more dense than the fluid will sink.

Pascal’s Principle

The principle stating that a pressure change occurring anywhere in a closed system of liquid is transmitted equally throughout the system, expressed as $\frac{\triangle F_1}{A_1} = \frac{\triangle F_2}{A_2}$.

Hydraulic System

A system based on Pascal's principle that uses differing surface areas to amplify force, allowing a small force on a small area to achieve a large force output on a large area.

Surface Tension

A force acting parallel to the surface of a liquid caused by the lack of balanced molecular bonds for molecules at the surface, often resulting in liquid forming drops.

Capillarity

The phenomenon where liquids rise up the walls of a container in a narrow space, explained by the relationship between adhesive and cohesive forces.

Adhesive Force

The force of attraction between two different types of molecules, such as water and glass, which in water is greater than the cohesive force.

Cohesive Force

The force of attraction between molecules of the same substance; liquids like mercury have high cohesive forces which lead to a convex meniscus.

Meniscus

The curve at the surface of a liquid in a container; it is concave when adhesive forces are stronger (water) and convex when cohesive forces are stronger (mercury).