AP Physics 2 - Unit 9: Thermodynamics

Heat

Energy transfered; not contained (exchanged only)

Temperature

A representation of average internal kinetic energy; contained (not exchanged)

Energy

ability to cause change

Thermal Expansion Equation Defined

Change in length (ΔL) of a solid material when heated or cooled = original length (Lo) times coefficient of linear expansion (α - alpha) for that material times change in temperature (ΔT)

Thermal Expansion Eq.

ΔL = LoαΔ𝑇

Volumetric Expansion Defined

Change in Volume (ΔV) of a solid material when heated or cooled = original volume (Vo) times coefficient of volume expansion (𝛽) of that material times change in temperature (Δ𝑇)

Volumetric Expansion Eq.

ΔV=βVoΔT

Kinetic Theory (proves ideal gases) First Law

The gas particles are VERY small (mostly empty space)

Kinetic Theory (proves ideal gases) Second Law

The number of particles is UNCOUNTABLY high

Kinetic Theory (proves ideal gases) Third Law

The collisions are ELASTIC (completely newtonian)

Kinetic Theory (proves ideal gases) Fourth Law

There are NO OTHER FORCES on the particles (no gravity)

Ideal Gas Law (Chemistry nerd verison) Eq.

P𝑉=nRT

Ideal Gas Law (Physics cool verison) Eq.

PV = NKbT

Heat Rate Eq.

(Q/t) = KAΔ𝑇/L

Conduction

Form of heat transfer; touch (cold hand holding warm hand till equilibrium)

Convection

Form of heat transfer; mass movement of particles (cold hand touching warm hand then letting go, then other cold hand touching warm hand then letting go, then another and another and another)

Radiation

Form of heat transfer; heat exchange by light

Maxwell Boltzman Distribution (shows up on AP test, otherwise useless)

Molecules per velocity VERSUS velocity.

As object gets hotter, peak gets lower and moves further right.

Area is constant thus molecules are. 

Amount of Heat Transferred When Temperature Changes Eq.

Q=MCΔ𝑇

Amount of Heat to Change Structure Eq.

Q=ML

Average Kinetic Energy Eq.

½mv²

Average Kinetic Energy of an Ideal Gas Particle Eq. 

3/2k_bT

Relation Between Energy to Temperature

1/2mv²_rms= 3/2k_bT

Total Internal Energy of a Ideal Gas

N x KE_avg = U OR N x 3/2k_bT

0th Law of Thermo

Once the two systems are in equilibrium, they stop exchanging energy

1st Law of Thermo

Energy is conserved

1st Law of Thermo Eq.

Q_in+W_on=ΔU

Whose your bestest most postive friend?

Q_in W_on!

Whose your most meanest negative friend?

-Q_out-W_by!

Isothermal Means…

Unchanging temperature (ΔT = 0)

Isothermal is a…

VERY slow process

Isothermal Eq.

Q_in+W_on=0

Isothermal Graph is the one in…

Orange

On a Isothermal Graph Check by…

P₁V₁=P₂V₂

Adiabatic Means…

Heat is 0 (Q_in & Q_out = 0)

Adiabatic is a…

VERY fast process (manipulates heat rate equation to have 0 heat added or taken)

Adiabatic Eq.

0 + W_on = ΔU

Adiabatic Graph is the one in…

Pink

On a Adiabatic Graph Check by…

NOTHING! P₁V₁≠P₂V₂

Isobaric means…

Unchanging pressure (ΔP = 0)

Isobaric Eq.

Q_in + W_on = ΔU 

Isobaric Graph is the one in…

Blue

Isochoric means…

(Δ𝑉 = 0); Isovolumetric

Isochoric Eq.

Q_in + 0 = ΔU

Isochoric Graph is the one in…

Green

What is the Area Under P Versus V Graph?

Work!

How do you tell if it’s W_on OR W_by ?

Direction of arrow; left is on, right is by.