Physics Flashcards
types of heat transfer
- conduction
- convection
- radiaton
Radiation heat transfer consists of
heat transfer due to electromagnetic waves
conduction heat transfer consists of
heat transfer due to direct contact
Conduction heat transfer consists of
heat transfer due to bulk flow movement.
Pressure at a given depth is called
hydrostatic pressure
Gases and Liquids are what kind of material?
Liquids
Density definition
Mass/volume
density of water is what?
1 g/mL = 1 g/cm^3 = 1 kg/L
Define specific Gravity
density of some liquid / density of water.
specific gravity = density of liqid/density of water
specific gravity of water is 1
Archimedes principle: define
the buoyant force on an object= weight of the fluid displaced by the object
Fb= weight displaced= ( mass displaced)(g) = ( density of fluid)(Volume submerged)(g)
What are the situations when comparing Fb to Weight such that it will float, sink or rise upward.
when FB = W , the object will float
when FB > W, the object will rise upward
when FB < W, the object will sink
Define hydrostatic pressure
if you apply pressure on a liquid, the pressure is transmitted equally to all parts of the liquid ( this is called pascal’s law)
Gauge Pressure
pgh because it igmore the atmosphereic pressure above the fluid….. it measures the amount of pressure beneath the surface.
Absolute pressure
is basically the pressure of something submerged in the ocean = pgh + atmospheric pressure
Pabs=Po + pgh
Continuity Equation
A*V=constant.
volume rate of a fluid is constant.
Surface tension is caused by what?
due to the attraction between molecules of the solvent.
Surface tension is caused by what?
due to the attraction between molecules of the solvent.
Stress definition
pressure exerted on an object F/A
Strain definition
the deformation of the object in the direction of the applied force divided by the original length
strain = Change in length/ inital length
Thermal expansion coefficient
alpha
when objects are cooled down or expanded, the object changes shape.
change in length = aloha * inital length * change in temperature.
MNEUMONIC + looks like alot
Chnage in volume Beta = 3* alpha
what do liquids and solids share in common and that seperates gases?
solids and liquids= incompressible
gases= compressible.
Adiabatic means what
- no heat transfer therefore it affects the internal temperature.
words to look for : quickly and rapidly
in an adiabatic compresion, temperature will…
increase
in an adiabatic expansion, temperature will
decrease
If the image is at infinity , then where is object
the object is at the focal length ,f
what is the formula for pressure and its units
Pressure = force / area
N/m^2 = pascal
Absolute pressure
P=P0+ pgauge
Po is not always 1 atm, it depends on the system
Pgauge= P-Patm = ( Po+pgz) - Patm
when Po=Patm
that is only when Pgauge = pgz
Absolute pressure aka hydrostatic pressure
P=P0+ pgauge
Po is not always 1 atm, it depends on the system
Pgauge= P-Patm = ( Po+pgz) - Patm
when Po=Patm
that is only when Pgauge = pgz
the specific gravity will indicate how much of the object is submerged
example if the specific gravity is 0.92 that means 92 % of the object is submerged under the water.
Papple/pwater = 0.92
Apparent weight in fluids
Fg-Fb= apparent weight in newtons
Force by gravity - force by bouyancy
Viscosity
unit in pascal seconds
- measure of internal resistance
- how resistance
Viscosity
unit in pascal seconds
- measure of internal resistance
- how resistance to flow is something
honey is the most viscous
- THINK DRAG IN FLUID
Flow rate definition
volume per second
this is a constant for a closed system and is independent of changes in a cross sectional area
Efficency definition
= ( Work out )/Work in
= ( Load * Load distance)/(Effort*effort distance)
Example - a pulley needs to be raised 3 meters who has a 10 N load there are 2 pulleys. the machine is 50 percent efficient.
effort distance - 2 pulleys * 3 = 6 m
solve for effort!
0.5 = ( 10*3)/( efffort * 6)
Efficency definition
= ( Work out )/Work in
= ( Load * Load distance)/(Effort*effort distance)
Example - a pulley needs to be raised 3 meters who has a 10 N load there are 2 pulleys. the machine is 50 percent efficient.
effort distance - 2 pulleys * 3 = 6 m
solve for effort!
0.5 = ( 10*3)/( efffort * 6)
bernouili equation
P1+1/2pmv^2+ pgh=P2+1/2pmv^2+ pgh=
P+pgh= static pressure
1/2 pv^2 = dymanic presure
if static pressure increases, then dynamic pressure decreases and vice verda.
P1 = energy density… Increase pressure therefore increase energy
speed of sound is what
343 m/s
and it changes as it travels though different mediums.
it travels fastest through solid –> liqiud and slowest in gas.
density defintion
mass/volume
1g/cm^3 = 1000 kg/m^3
Lyman series is what
lower in wavelength but INCREASE frequnecy …. ultraviolet
it goes down to n=1
Balmer series goes down to what orbiral level
n=2 COLOR ( partially visible)
If a test charge is positive (+) what direction is the force and the Electric field?
Force and the electric field are in the same direction
F=qE
If a test charge is negative, what direction is the force and the electric field?
Force and the electric field is in opposite directions
F=qE.
Force on a moving charge equation
Fb= qVBsin(theta)
Fb=ILBsin(theta) on a wire0
Use the right hand rule ..
Thumb = velocity
Finger = lines
Palm=force
Back of palm is used for negative charge
Magnetic Fields equation for a straight long wire
B= ( Uo I)/(2Pir)
Unit is tesla
Magnetic fields equation for a loop of current carrying wire
B= ( Uo* I ) / ( 2r)
magnetic field unit
T = tesla = Ns/MC =
Electric potential
positive test charge will move spontaneously from high potential to low potential.
Negative test charge will spontaneously move from low potential to high potential.
Poiseuille law
Q= ( pi r^4 delta P)/ ( 8nL)
flow rate is directly prrportional to change in pressure and radius to the 4th power
When a critical speed is exceeded what happens?
flow becomes turbulence and it forms eddies
when critical speed is not exceeded what happens
flow is laminiar
Specific gravity indicates the percent of volume is submerged
Example 0.92 specific gravity = 92 % of its volume is submerged
therefore any object whose specific gravity is less than 1 will float in water