There are four states of matter…

SolidsLiquidsGases

Plasmas

Fluids are materials thatFlow and have no

Definite shape of their own.

Pressure is a measure of how Much force is applied per

Unit area.

OR…

P = FA

The SI unit for pressure is N/m2

This is also called the Pascal (Pa).

The Pascal unit is very small.

It is so small that the averageAir pressure here is about

1.01 X 105 Pa!!

The force exerted by a gas Can be understood by using the

Kinetic-Molecular Theory…

This theory states that gases areMade up of very small particles;

These particles are in constant Random motion;

And the forces that are exerted byThe particles hitting the container

Are the cause of gas pressure.

A woman weighs 495 N and is Wearing shoes that cover an Area of 412 cm2. What is the

Average pressure that her shoes Exert on the floor?

P = 1201.5 Pa

A gas is very similar to a liquid.

A gas has low density,Density depends on pressure,And expands to fill container

The ideal gas law relates Gas volume, pressure, and

Temperature.

You may have seen it likeThis in Chemistry…

PV = nRT

R = proportionality constant = 0.08206 L atm K -1 mol -1

P = pressure in atm V = volume in liters

n = moles T = temperature in Kelvins

P1V1

T1

P2V2

T2

=

This is most useful when Solving problems.

That formula can be rearrangedTo look like this…

Helium is in a container beingCompressed. The initial volume,

Pressure, and temp are: 15L, 2 atm, 310K. If the volume

Is decreased to 12L, and the Pressure is increased to 3.5 atm,

Find the final temperature.

T2 = 430 K

Plasma is the gas like state Of matter made up of positively

Charged ions or negatively Charged electrons or a mixture

Of them.

This is another fluid state of matter.

You have all seen plasma…

Plasma exists everywhere, Stars, lightning, neon signs, etc.

The main difference between a Gas and plasma is that a gas

Cannot conduct electricity and A plasma can.

Cohesive forces are forces Of attraction between molecules.

Surface tension is a result of Cohesive forces, and is the Tendency of the surface of a

Liquid to contract to the Smallest area possible.

( a sphere)

Adhesion is the attractive force That acts between particles

Of different substances. (like water sticking to glass)

Capillary action is the rise of Water in a thin tube that occurs

Because of adhesion.

An ideal fluid is a fluid that hasNo internal friction or viscosity

And is incompressible.

Viscosity is the amount of“flow” a fluid has.

The higher the viscosity, the Slower it flows. (thicker)

So the lower the viscosity, The faster a fluid will flow.

(thinner)

Evaporation is the escape of particles from a liquid.

This has a cooling effect.

A volatile liquid that evaporatesVery quickly.

(many times with explosive ends)

Condensation is the process Where particles return to the Liquid phase. This is due to A decrease in temperature.

Pascal’s Principle states that The shape of any container has

No effect on the pressure of The fluid.

Or, if a pressure is created in a Closed container, it is transferredThroughout the entire container.

A car weighing 1.2 X 104 N sits On a lift with an area of 0.9 m2.Compressed air exerts a force On a piston to lift the car. The

Area of the piston is 0.2 m2. How Much large is the force needed

To lift the car?

F = 2.7 X 103

When you are swimming, you feelThe pressure of the water

Increase as you dive deeper. ThisPressure is a result of gravity, Because of the weight of the

Water above you.

P = ρhg

P = ρhg

The pressure that a column of Water exerts on a body is equal

To the density of the water timesThe height of the column timesThe acceleration due to gravity.

A reservoir behind a dam is 17 m Deep. What is the pressure of the

Water at the base of the dam?What is the pressure of the water

4 m from the top of the dam?

The buoyant force is a force That acts upward on an object

Submerged in a liquid or Floating on the liquid’s surface.

It was first discovered by Archimedes.

Archimedes’ principle is as follows..

Any object completely or partiallySubmerged in a fluid

Experiences an upward buoyant Force equal in magnitude to

The weight of the fluid Displaced by that object.

A floating object cannot be Denser than the fluid

In which it floats.

A floating object’s buoyant force Is equal to the object’s weight.

Fb = ρVg

A cube of aluminum (1.0 X 10-3)Is submerged in water. The

Density of aluminum is 2.7 X 103. What is the magnitude of the

Buoyant force acting on the metal?What is the apparent weight of

The block?

Fb = 9.8 N Fa = 16.7 N

Bernoulli’s Principle tells us That when the pressure in

A fluid decreases, the Velocity increases.

This is the theory that tells Us how an airplane flies.

Structures & Types of Solids

Crystalline Solids: highly regular arrangement of their components

Such as table salt

Amorphous solids: considerable disorder in their structures (glass).

Most solids are much more Dense than their liquid

Counterparts, water is the Exception since it is most

Dense at 4 °C.

This is because as a liquid Freezes its molecules fit closer

together.

Elasticity is the ability of a Solid object to return to itsOriginal form after external

Forces are exerted on it.

If too much deformation Occurs, the object will break.

Thermal expansion is the Increase in length and volume

Of a material when heated.

This is very common, look at a Bridge next time you drive over it,

You will see metal bands there That connect the road.

How big those bands are dependantOn how much temperature change

There is during the year.

The amount of linear expansionCan be found with…

ΔL = αL0ΔT

α is called the averageCoefficient of linear expansion.

There is also area expansion…

ΔA = γA0ΔT

ΔV = βV0ΔT

And Volume expansion…

A metal bar is 2.6 m long at room Temperature, 21 °C. The bar is Put into an oven and heated to 93 °C. It is them measured and

Found to be 3.4 mm longer. What isThe coefficient of linear expansion

Of this metal?

α = 1.8 X 10-5