IB Physics HL Themes A-C

archimedes’ princple

buoyancy force = weight of displaced fluid, volume of object = volume of displaced fluid

what does buoyancy force also equal?

difference in object’s weight in air vs. fluid

toricelli equation

v = root(2gdeltah)

what is v in torcelli’s equation?

exit velocity from hole

what is deltah in torcelli’s equation?

height between exit hole and height of water

in the equation for buoyancy force, rho refers to the density of what material?

the fluid

in the equation for buoyancy force, V refers to the volume of what material?

of the displaced fluid or of the object

formula for density

mass/volume

viscous drag force

force acting on a small sphere opposing its motion through a fluid

3 conditions of static equilibrium

sum F y = 0, sum F x = 0, sum torque = 0

pushing on a block causes a(n)

increase in normal force, increase in friction, and decrease in acceleration

pulling on a block cause a(n)

decrease in normal force, decrease in friction, and increase in acceleration

in an atwood’s machine …

the a going down will be negative, the a going up will be positive

when a rope is broken by block, with either side’s tension being T1 and T2, does T1 = T2?

no

if an elevator breaks and is in free fall, what is the apparent weight of the dude inside?

0N

if an elevator breaks and is in free fall, is ma positive or negative?

negative

in elevator problem, normal force can also be …

tension

in elastic collisions,

KE and momentum are conserved

in inelastic collisions,

KE is not conserved but momentum is

in a perfectly inelastic collision,

the colliding bodies stick together

area under a force time graph

impulse (J) (also delta p)

1 N =

1 kg(m)(s^-2)

unit of J / p

Ns

KE also =

p²/2m

perfect elastic equation

KE = KE

on a flat, circular curve, what is the centripetal force?

friction

on a banked, circular curve, what is the centripetal force?

the center pointing component of normal force

at what point on a vertical circle is tension the greatest?

6 o’clock

convert velocity to angular velocity

v = r(omega)

perfectly elastic collision relative velocity equation

u1 + v1 = u2 + v2

area under a force displacement graph

work

when a sphere rolls down an incline plane, what force provides the torque to spin it?

friction

angular momentum symbol

L

Radiation

transfer of energy by electromagnetic waves (the sun)

Convection

movement of groups of atoms/molecules w/i fluids that arises from variations in density (hot air rises)

Conduction

heat transfer through a solid via atomic vibrations (collisions), requires physical contact (touching a hot metal cup)

four contributors to global warming

1. solar constant (we don't effect) 2. albedo 3. emissivity (related to GHGs) 4. GHGs - as they increase resonance causes an increase in KE and hence temperature

Greenhouse Gases

carbon dioxide, nitrous oxide, methane, and water vapor

four assumptions of kinetic theory of an ideal gas

all collisions are perfectly elastic, no IMF's (all KE), at any point equal number of molecules moving in any direction, enough molecules to make statistical averages

Why temperature and pressure are directly proportional

An increase in temperature causes and increase in average KE by definition, and hence increases the speed of the molecules. This leads to more collisions between the molecules and the container, and hence an increase of the gas's force on the container. As pressure is a measure of force per unit area, this leads to an increase in pressure.

what is meant by total internal energy of an ideal gas

total random kinetic energy of the particles of the gas

non-ohmic

non-constant resistance

ways to fix climate change

greater efficiency of power production, use of combined heating and power systems, transitioning to electric vehicles

carnot efficiency

(TH - TC)/TH * 100

actual efficiency

Wtot/sum of +Q * 100

most efficient energy process

isothermal

second most efficient energy process

adiabatic

if isothermal, __ = 0

delta U

if isovolumetric, __ = 0

work

if adiabatic, __ = 0

Q

in P = 1/3rhov², what is v²?

mean square speed

unit of pascals are equivalent to

N/m²

for circuits, rho = ? and R = ?

resistivity, resistance

a lower cross sectional area corresponds to a

higher resistance

a higher length corresponds to a

higher resistance

characteristics of charge

charge is quantized, charge is conserved

ideal resistor = ___

resistance won’t change over time

‘unloaded’ potential difference =

no resistor attached

info from a x v. t graph

period and amplitude

info from a x v. pos graph

wavelength and amplitude

energy is applied ___ to a longitudinal wave

horizontally

energy is applied ___ to a transversal wave

vertically

in a sound wave, frequency and pitch are ___ proportional

directly

after diffraction, what three variables remain the same?

frequency, wavelength, and speed

after diffraction, what changes?

direction of propagation and pattern of ways

index of refraction and density are __ proportional

directly

when light enters a more dense medium, ___

velocity and wavelength decrease, light bends towards the normal line, frequency remains the same

total internal reflection occurs when ___

the incident angle is greater than or equal to the critical angle

to solve for the critical angle, ___

set theta 2 equal to 90

for the double slit equation, d =

distance between slits

for the double slit equation, D =

distance from slits to screen

for the double slit equation, s =

distance from central max to next max

for double slit, a more separated fringe pattern =

greater distance from central max to next max (s)

simple harmonic motion

repeated motion around an equilibrium position where the restoring force on the object is proportional to its displacement and points towards equilibrium

as harmonics increase, ___ remains constant

velocity

critical angle when ___ dense to ___ dense

more, less