Physics Flashcards
PV graph for different rxns
isobaric = MOST WORK DONE (biggest area)
ashesion / cohesion
high adhesion = concave
high cohesion = convex
conduction
direct contact between surfaces to transfer heat
convection
transfer of heat by motion of fluid (air, liquid) over material
convection ovens cook faster (use both convection + radiaton)
radiation
transfer of energy by EM waves, can transfer through vacuum
phase change
no change in temp, NRG only to change state
q = mL (L = latent heat of transformation)
sublimation = solid-gas. deposition = gas-solid
isobaric process
pressure constant
the normal PV curve is straight line
W = PV, most work done
isothermal process
temperature constant (internal NRG constant, U = 0)
Q = W
isovolumetric process
no volume change, W = 0! (no area)
U = Q
adiabatic process
no heat exchange (Q = 0)
U = W
weight of a given volume using density
Fg = p V g
needed in buoyancy Qs
pressure
ratio of Force:Area, N/m^2 = Pa
P = F/A
F = P x A
hydrostatic pressure, dynamic pressure, atmospheric pressure
absolute pressure = Patm + pgh
guage pressure = difference between absolute and atm pressures
pascal’s principle
- fluid is incompressible, force/pressure is distributed
- hydruolics!!
- VOLUME moved on both sides must be equal, so A1d1 = A2d2
- PRESSURE on both sides must be equal, so F1/A1 = F2/A2
- factor that d1 is larger than d2 is same factor that F2 is larger than F1
- eg. press down 3X as far, create force on other side 3X as powerful
viscosity
resistance of fluid to flow
usually assume it is negligible (need this for Bernoulli)
turbulent flow = occurs past critical speed
flow RATE
- ** flow rate is independent of changes in AREA or SPEED**
- v1A1 = v2A2
- flows faster when area is smaller, but Q will be constant!!
concept of breathing and pressure
venturi flow meter
- as area decreases, v increases, so dynamic P increases
- this means static P decreases – fluid doesn’t push as much, so the height of fluid in the column is LOWER
- referring to h = height of fluid column from static P
charge of electron/proton
1.6 x 10^19 C
either + or -
when placed 1m apart, would 1C of electrons or 1C of protons have greater acceleration?
since both have the same charge (Q), Fe is the SAME
Fnet = Fe
Fnet = m x a
electrons have low mass, therefore higher acceleration
field lines
show direction a test charge would move (+)
from a + point charge = outwards
from a - point charge = inwards
force will be in same direction of field if (+), opp direction if (-)
electric potential energy
- potential energy between 2 charges
- EPE proportional to 1/r for (+) charge
- HIGH EPE for (+) charges brought CLOSER
- HIGH EPE for (-) charges moved FURTHER
electric potential
- ratio of EPE to magnitude of charge: V = U/q
- V = kQ/r
voltage
- potential difference between 2 points at different “r”
- the WORK to move test charge (+ or -) from INIFINITY to a point in E field
- (+) charge will move spontaneously to low EPE (moves away) from high potential to low potential ( ΔV = NEGATIVE)
- (-) charge will move spontaneously to low EPE (moves together) from low potential to high potential ( ΔV = POSITIVE)
- **move from high potential (voltage) to low potential
- think: emf
equipotential lines
ΔV between any 2 points doesn’t depend on path but the difference in voltage (depends on r)
cirlce lines around point charge with same voltage
magnetism
- any moving charge makes a magnetic field
- unit = Testla (T)
diamagnetic
no unpaired e-
no field
repelled by a magnet
paramagnetic
unpaired e-
weakly magnetized in field
dipoles allign
field removed, orient randomly again
ferromagnetic
unpaired e-
strongly magnetized y field
eg. bar magnets, N and S poles
force on a moving charge
F = qvBsinθ
* Force = 0 when θ = 90 or 180
* so any charge moving parallel/antiparallel to magnetic field feels NO FORCE
force on a current carrying wire
*
Fe/E/U/V
summary table:
metallic conductivity
sea of electrons
metals
electrolytic conductivity
concentration of ions in solution
eg. Na+Cl-
current
- I = Q/t
- how much charge is moving past a point in a certain length of time
- flow of POSITIVE CHARGE (actual current is opposite)
conductance
1/resistance
conductance and resistance are inversely proportional
parallel circuit notes:
- pathway with LOW R = HIGH I
- when n# of identical resistors in parallel, Rtotal = R/n
- resistance in parallel DECREASES as you add more resistors (capillary beds)