AP Physics 2

This is a work in progress

environment

anything outside the system

boundary/interface

separates the system and the environment

kinetic theory of matter

all matter is composed of small particles which have space between them and are in random motion

evaporation

water molecules collide and get knocked off

atomic number

number of protons

the number of electrons is equal to the number of ___ if neutrally charged

protons

atomic mass is sum of

protons and neutrons

assumptions of an ideal gas

All collisions, both between the molecules themselves, and between the molecules and the walls of the container, are perfectly elastic. (That means that there is no loss of kinetic energy during the collision.)

There are no (or entirely negligible) intermolecular forces between the gas molecules.

Gases are made up of molecules which are in constant random motion in straight lines.

The volume occupied by the molecules themselves is entirely negligible relative to the volume of the container.

pressure

particle collisions with the wall or container

source of temperature

average kinetic energy of an objects atoms

heat and temperature ____ the same thing

are NOT

heat

transferring or exchanging thermal energy (between system and environment)

temperature is directly proportional to

P*V

maxwell distribution area meaning

more area means more particles

names of the 4 special gas processes

Isobaric - pressure constant

isothermal - temperature constant

isochoric - volume constant

adiabatic - no heating (Q=0)

0th law of thermodynamics

thermal equilibrium is based on temperature. If two systems are in thermal equilibrium with a third system, then they must be in thermal equilibrium with each other

1st law of thermodynamics

there are two ways to change the thermal energy of a system, heating and work2n

2nd law of thermodynamics

Heat flows spontaneously from hot to cold. Entropy (disorder) of an isolated system is always increasing

3rd law of thermodynamics

kinetic energy of particles at absolute zero is zero. Entropy is zero

gas expands

positive work done by gas to environment

loss of energy means ___ will go down because the ___ decreases

temperature, speed

gas contracts

environment doing positive work on gas

heat engines

convert thermal energy into mechanical energy

specific heat

a characteristic of matter that describes how difficult it is to change temperature. AKA amount of energy required to raise 1kg of a substance by 1 kelvin

Methods by which heating can occur

Conduction, convection, radiation, evaporation

radiation

heat transferred by electromagnetic waves

as heat (Q) is transferred into or out of an object, its temperature will change unless

there is a phase transition

heating takes

time

insulator

charge remains localized

conductor

allows electric charges to flow through it

Grounding

our body is a conductor so charges are conducted through our body to the earth

3 ways to charge an object

friction (rubbing), conduction (touching), induction (not touching)

superposition for electrostatics

net force on one charge is vector sum of all other electrostatic forces

electric field

describes the force a positive charge would feel

electric field lines

never cross, closer together means larger magnitude, start on positive charges and end on negative charges

electric field inside a conductor

is zero everywhere unless there is a point charge inside it

electric potential

how much potential energy a charge would have if it was in the empty spaceec

electric potential energy

energy stored in a charge based on where it is in space

potential difference

work done per unit charge in moving from two equipotential surfaces

synonyms for potential difference

voltage, emf (electromotive force)

positive charges move from ___ electric potential to ____ electric potential

high, low

negative charges move from ___ electric potential to ____ electric potential

low, high

capacitor

two parallel plates that have an equal and opposite amount of charge. purpose is to store and be able to quickly dump energy

capacitance of a capacitor

ratio of charge on either plate and the potential difference between the plates, essentially it measures the capacitors ability to store charge

a point charge inside a metal sphere would

polarize the sphere but the overall charge of the sphere would remain the same

do electrons or protons move during conduction

electrons

if two points have a potential difference between them and they are connected with a conductor, negative charges will flow from ____ concentration to a ______ concentration

higher, lower

electric current

measures the amount of charge passing a given point every second

battery

supplies a potential difference to maintain a continuous flow of charge

we say that current is the ____ flow of charges but in reality it’s actually ____ charges

positive, negative

resistor

function is to use up voltage

voltmeter

measures potential difference between two points, high resistance

ammeter

measures current, is like a flow meter, low resistance

are light bulbs ohmic

NO

omh’s law is valid as long as

the temperature remains constant

junction rule

conservation of charge, total current coming into a junction must equal the total current leaving the junction

loop rule

conservation of energy, total voltage drops and gains must total to zero as you travel around a closed loop

parallel branches have the same

potential difference

short circuit

path of no resistance

resistors in series

add resistances togetherr

resistors in parallel

inverse of the summation of the inverse resistances

ideal battery

no internal resistance

internal resistance

usually modeled as an ideal source in series with a small internal resistor

capacitor in series

inverse of the summation of the inverse capacitances

capacitor in parallel

add the capacitances together

for a capacitor in series what is the same for all plates

q

what is the same for capacitors in parallel

potential difference

an empty capacitor behaves like

an ideal wire

a full capacitor behaves like

an open switch

current is

undiminished throughout a circuit, same amount of current everywhere unless there are parallel branches

like poles ____ unlike poles ____

repel, attract

what happens if a magnet is broken into two

both pieces has a pair of poles (magnetic poles never appear in isolation)

compass needle will align itself ____ to the external _____ _____

tangent, magnetic field

magnetic field lines

always form complete loops (N→S outside) (S→N inside)

where is the magnetic field strongest for a bar magnet

inside the magnet

sources of magnetic fields are _____ ______

moving charges, and in turn these magnetic fields exert forces only on other moving charges

all charges produce ____ fields

electric

moving charges produce ____ fields

magnetic

magnetic force and magnetic field (are/are not) in the same direction

are not

magnetic forces cannot perform work because of their

perpendicularity

if the velocity and magnetic fields are perpendicular the path of the charge is

a circle

the right hand rule is used for ____ charges

positive

the left hand rule is used for ___ charges

negative

3 different RHR’s

1. thumb in direction of current, the way the fingers curl gives magnetic field direction

2. Fingers pointing towards velocity or current, curl B, thumb is direction of the force

3. curl current, thumb gives magnetic moment

magnetic moment

points in the direction of the B field that the object created, not the one it’s experiencing. Is a measure of how much torque a dipole will feel in a magnetic field

into/out of page symbols

permeability

the ability to be magnetized

solenoid

loop stretched out to form a spiral

describe magnetic field of a solenoid

uniform inside the solenoid, zero outside

current carrying wires carrying currents in the same direction will ___ while current carrying wires carrying currents in the opposite direction will ____

attract, repel

magnetic particles never change an objects ____

speed (they only turn them)

electromagnetic induction

a magnetic field can be used to induce current in a wire. source of the current is the establishment of motional emf due to the CHANGE in magnetic flux

magnetic flux

measurement of how much magnetic field penetrates a surface

Lenz’s Law

the flux is ____ and it is ____. therefore the loops B field will be (opposite)

reflection

ability of light to bounce off of a surface

two types of reflection

specular: smooth surface θ_i=θ_r

diffuse: surface is rough/uneven, light rays are scattered

angle of incidence is measured to the

normal

refraction

apparent bending of light

in phase

waves of light match up peak to peak and trough to trough

wave speed depends on the

medium