Physics Equations Flashcards
Photon energy
E=hf=hc/(wavelength)
Venturi effect
Oxygen pressure is the sum of the oxygen static pressure P and the oxygen flow pressure (density x volume-squared/2)
Acceleration
velocity/time with changing direction
Uniform motion - find a
d=1/2(v0+v)t
Uniform motion - find d
v=v0+at
Uniform motion - find v
d=v0t+1/2at2
Uniform motion - find v0
d=vt-1/2at2
Uniform motion - find t
v2=v02+2ad
Gravitational acceleration
10m/s2
Projectile motion - horizontal displacement
x=v0t
Projectile motion - vertical displacement
y=v0t+1/2(-g)t2
Projectile motion - horizontal velocity
vx=v0 (constant)
Projectile motion - vertical velocity
vy=v0+(-g)t
Projectile motion - horizontal acceleration
ax=0
Projectile motion - vertical acceleration
ay=-g
Newton’s Second Law
Fnet=ma
Newton’s Law of Gravitation
Fgrav=G(M1M2/r2)
Gravitational Acceleration
g=G(M1/r2)
Kinetic Friction
Ff= μk F(normal)
Static Friction
Ff= μs F(normal)
Parallel Force due to Gravity
F=mgsinΘ
Perpendicular Force due to Gravity
F=mgcosΘ
Center of Mass for Point Masses
X=(m1x1)+(m2x2)+(…)/m1+m2+m3
Centripetal Acceleration
a=v2/r
Centripetal Force
F=ma=mv2/r
Torque
τ=rFsinΘ
Work
W=FdcosΘ
Power
W/t
Kinetic Energy
KE=1/2mv2
Work-Energy Theorem
W=ΔKE
Potential Energy
PE=mgh
Total Mechanical Energy
E=KE+PE=1/2mv2
Mechanical Advantage
MA=F(resistance)/F(effort)
Momentum
p=mv
Impulse
J=Δp=Δmv=FΔt
Angular Momentum
L=rvm
Efficiency (%)
W(output)/E(input)
Work done by gas piston
W=PΔV
Change in Internal Energy
ΔE=Q-W
Change in absolute temperature of an ideal gas
Constant Volume - Q=nCT
Density
ρ=m/v
Specific Gravity
ρ(substance)/ρ(water)
Weight
w=mg
Pressure
F/A
Hydrostatic Gauge Pressure
P(gauge)=ρ(fluid)gD
Total Hydrostatic Pressure
P(total)=P(surface/gas)+P(gauge)
Archimedes Principle
F(bouy)=ρ(fluid)V(sub)g
Apparent weight of submerged object
apparent weight = w (object) - F (bouy)
Pascal’s Law
F1/A1=F2/A1
Flow Rate
f=Av
Continuity Equation
A1V1=A2V2
Bernoulli’s Equation (Ideal Fluid)
P1 + 1/2ρv2 + ρgy = P2 + 1/2ρv2 + ρgy
Floating Object Relationship
V (sub)/V=ρ(obj)/ρ(flu)
Toricelli’s Result
v(efflux) = √ 2gD
Stress
Stress=F/A
Strain
Strain =ΔL/L0
Hooke’s Law
Stress=modulus x strain
Tension or compression
ΔL=FL0/EA
Shear
X=FL0/AG
Coulomb’s Law
F(elec)=k (lQl lql/r2)
Electric field due to point charge (Q)
E=k (lQl/r2)
Electric force by field
F=qE
Electric Potential
EP=k(Q/r)
Change in Electrical PE
ΔPE = qΔEP = qV
Work done by electric field
W= - ΔPE
Change in KE
ΔKE = - ΔPE = W (e field)
Current
I=Q/t
Resistance
R= ρ (L/A) ρ=resistivity
Ohm’s Law
V=IR
Resistors in series
R= R1 + R2 + R3…
Resistors in parallel
1/R = 1/R1 + 1/R2…
Power of circuit
P=IV=I2R=V2/R
Charge of parallel plate capacitors
Q=CV
Capacitance (no diaelectric)
C=ε(A/d)
Capacitance (with diaelectric)
C=KC(without)=Kε(A/d)
Electric field in parallel plate capacitor
V=Ed
Stored potential energy in capacitor
PE=1/2 QV = 1/2 CV2 = Q2/2C
Capacitors in parallel
C=C1 + C2 + …
Capacitors in series
1/C=1/C1+ 1/C2 +…
Magnetic force on moving charge (q)
F=-qvB F= lqlvBsinΘ sinΘ is angle between v and B
Hooke’s law (spring)
F=-kx
Elastic potential energy
PE = 1/2kx2
Spring-block oscillator frequency
f=(1/2π)(√k/m)
Simple pendulum frequency
f=(1/2π)(g/l)
Period/frequency
T=1/f
Wave equation
v=λf
Standing-wave (harmonic) wavelength
λn=2L/n (n=1, 2, 3) λn=λ1/n
Standing-wave (harmonic) frequencies
fn=(v/2L)n fn=nf1
Velocity of sound
v=√B/ρ
Intensity
I=Power/Area
Intensity level
β=10 log (I/I0)
Harmonic frequency (sound) - open end
f=nv/2L
Harmonic frequency (sound) - closed end
f=nv/4L
Harmonic wavelength (sound) - open end
λ=2L/n
Harmonic wavelength (sound) - closed end
λ=4L/n
Doppler effect
f= (v+/-vD)/(v+/-vS)fs
Frequency of a beat
f= lf1 - f2l
Index of refraction
n=c/v
Law of reflection
Θ1=Θ1`
Law of refraction (Snell’s law)
n1sinΘ1=n2sinΘ2
Mirror-Lens equation
1/o + 1/i = 1/f
Focal length
f = R/2
Magnification
m = -i/o
Lens power
P = 1/f P(combination) = P1 + P2
Photoelectron Energy
KEmax = hf - energy potential
Stopping Voltage
-eVstop=KEmax
