Physics Flashcards
convection
Transfer of E via heat by movement of liquid
conduction
flow of E from higher temp to lower
radiation
transfer of E through vacuum
Resistors in series
Rt = r1 + r2
Resistors in parallel
1/rt = 1/r1 + 1/r2
Capacitors in parallel
C = c1+c2
Capacitors in Series
1/C = 1/c1 + 1/c2
Voltage in parallel
V = v1 = v2
Voltage in series
V = v1 +v2
sin30
1/2
cos30
√3/2 = .867
sin0
0
cos0
1
sin45
√2/2 = .707
cos45
√2/2 = .707
sin60
√3/2 = .867
cos60
1/2
sin90
1
cos90
0
Equation for Work
W = FdcosA
Pendulum Period T=
T=2pi√(L/g)
Impulse, J
J= change in momentum
J=Ft
What happens to sound wave as it travels? Eg circle…
E?
I?
Energy remains the same at all d from source of sound, neglecting air resistance.
the Intensity changes …Power = IA A=area of coverage. If P stays same, as A increases, intensity dec
capacitor
stores electric charges with potential difference, V, between them
Speed of light, f and wavelength. Equation?
Frequency x wavelength = speed of light, c
c = 3x10^8
maximum velocity
occurs when acc=0, cannot possible go any faster
terminal velocity
will always involve a drag force in terms of velocity
kWh
kilowatt hour - this is a unit of E bc Watt = E/t so Watthour = Et/t = E
normal force
at the top of a loop?
normal force is always pointing away from the surface from which an object is touching
on a loop. when the object is at the top of the look, the normal force is pointing downward
signal to noise ratio
signal should be high, noise should be low
100:1 is way better than 1:1
E field strength at distance r
E = kq/r2
man jumps off deck and throws ball directly out at same time. which lands first?
land at same time.
even though ball has horizontal v, the ball and man’s acc due to gravity is the same
vf2 =
vf2 = vi2 + 2ax
vf =
vf = vi + at
deltax =
x = vit + 1/2at2
beats
difference in frequencies arriving at a point
creates constructive and destructive interference
torque
t = rfsina
E of a wave =
E = hf where h is Planck’s const. and f is freq
remember v=f x wavelength
sound waves travel fastest through what medium?
solid, liq then gas
can sound waves be longitudinal?
no not usually
longitudinal waves are like seismic waves
standing = transverse = harmonic waves are sound
does light have sound freq and period?
does sound?
yes and yes. Both are waves
what kind of wave is sound? Meaning what about the medium displacement?
longitudinal, meaning medium is displaced in the direction of the wave
what kind of wave is light? Meaning what about displacement?
light is transverse, meaning displacement is perp to wave
light travels fastest through what medium?
air, liq, solid (glass etc)
what waves experience diffraction
all waves, sound and light
E in a spring?
E = kx2
V =
in a circuit
V = iR V = P/i V = CQ
capacitance eq
C = A/d where A is area of plates, d is distance between C = Q/V
heat of vaporization
amount of heat required to change the state of a substance
relationship between static and dynamic friction coefficients
dynamic is always less than static. This makes sense, as the coeff for static should be way higher to keep the object completely stationary. It harder to over come friction from a stand still than from a moving position
Gravity Eq. F =
F = Gm1m2/r2
torque T =
t=rfsina
a is between r and F
Circ motion
Fc =
ac =
Fc = mv2/r
ac = v2/r
Pulley
W input =
W output =
efficiency =
W in = effort x effort distance
W out = load x loadx
effic = out/in
Circuits and Power
P =
P = iV
P = i2R
P = V2/R
Electrostatics
E =
E = F/q
E = V/d
electrostatics F
F = kq1q2/r2
Electric potential V =
V = kq/r
V = W/q
Va - Vb = Wab/q
Electric potential E, U =
U = W = qV
U = kqQ/r
Pressure P
P = P0 + dgh
where P0 is pressure at the surface and d = density
P = F/A (think spike heels)
Magnetic field B
loop
straight
B = ui/2r at the center of a Loop where u = mew naut
B = ui/2pir (think you have to take into account the roundness of the wire)
Magnetic F
F = qvBsina
F = iLB sina
thermal expansion
inc in T solid will expand
change in L = aLchangeinT where a is alpha and change in is delta
Volume expansion
as T inc, liq expands
^V = BetaV^T where ^=delta
Specific heat
Heat gain and loss
Q = mc^T c = specific heat of substance Q = heat gain/loss
Heat of transformation
Phase change
Q = mL
concave with object at focal point: real or virtual?
upright or inverted
real and inverted
also true for anything further than focal pt
convex with object at focal?
virtual and upright
also tru for anything further than focal pt
elastic collisions
what is conserved?
kinetic E
inelastic collisions - is Kinetic E conserved?
no, can be converted to other forms of E
what is heat of transformation?
Equation?
what kind of process is this?
amount of heat required to change the phase of 1 kg of a substance
Q = mL
isothermal! like changing from ice to water at 0C
what is the area underneath a P vs V graph?
it is the work done in a system
what is the law of thermodynamics?
Equation?
What happens adiabatic?
constant V?
closed cycle?
DeltaU = Q - W Q is heat lost or gained, W is work, U is energy in system
Adiabatic, no change in heat, Q = 0
Constant v, piston isn’t moving, W = 0
closed, U = 0
in any thermodynamic process that shifts eq, what will happen to S?
it will either increase or remain the same
a positive charge will move in what direction of the E field?
the same direction
a neg charge will move in what direction of the E field?
opposite of E
what is electric potential energy, U?
the amount of energy needed to move a charged particle from infinity to a point
U = qV = qEd = kq1Q/r
dipole moment p =
does it feel a force?
p = qd
no force, but does experience torque which causes it to rotate to align with E field
Electric Potential, V =
what is the unit?
V = W/q
the amount of work required to move a pos test charge to infinity to point. Work per charge
Unit is volts!
What is potential difference?
VOLTAGE!
when 2 oppositely charged plates are separated by distance, d, a potential difference exists between them, V = Ed = W/q = kQ/r
Fbuoy =
Archimedes’ principle
Fbuoy = p(fluid)gV(submerged)
and Weight, W = pVg, so it makes sense that Fbuoy = W
The buoyant force is equal to the weight of the displaced fluid.
when will an object float or sink?
float when the weight of the displaced fluid is greater than the object or equal to it
sink if the displaced fluid is less than the weight of the object
what are the equations of a system with 2 pistons?
F1/A1 = F2/A2 A1d1 = A2d2 F1d1 = F2d2
what creates a magnetic field, B?
moving charges and permanent magnets
what direction do magnetic field lines flow?
from north to south
a charge moving in a B experiences what kind of F?
When is F=0?
F = qvB (sin a)
F = 0 when the charge is moving parallel or antiparallel to the B
what is current and in what direction does it flow?
current is flow of e charge
direction is the direction that pos charge would flow…from high to low potential
What is capacitance and the equations?
Capacitance is the ability to store charge per unit voltage
C = Q/V C = kEA/d don't worry about k or E, just A and d here
what is the Energy stored by cap?
U = 1/2QV^2 = 1/2CV^2
