Physics 202 Cheat Sheet

1 MotionConstant Acceleration Processes Constant Angular Acceleration Processesa = constant α = constantv = v0 + at ω = ω0 + atx = x0 + v0t+

1

2at2 θ = θ0 + ω0t+

1

2αt2

v2 = v20 + 2a∆x (Handy Eq.) ω2 = ω20 + 2α∆x

At a Points = rθv = ωra = αr

F = ma τ = IαW = F∆x W = τ∆θP = Fv P = τωKE = 1

2mv2 KE = 1

2Iω2

p = mv L = IωRollingFfriction = µN (slip) scm = rθ (no slip)

vcm = ωr (no slip)acm = αr (no slip)

Systems of ObjectsFnet,external = Macm τnet,external = Iαcm

2 UnitsSI: m, kg, sarea: m2, volume: m3

velocity: m/s, acceleration: m/s2

Common Conversions

1. 3600 s = 1 hour

2. 1.609 km = 1 mile

3. 1 m/s = 2.237 mi/hr

4. 745.7 Watts = 1 hp (HorsePower)

5. 1 mL = 1 cm3

Common Physical Constants

1. c = 2.998× 108 m/s (Speed of Light)

2. g = 9.81 m/s2 = 32.2 ft/s2

3. G = 6.674× 10−11N ·m2/kg2

4. ρair = 1.2041 kg/m3 = 0.0012041 g/cm3

5. ρwater = 1 g/cm3 = 1000 kg/m3

6. R = 8.314 Jmol·K

= 82.057 mL·atmmol·K

7. P0 = 1 atm = 101.325kPa (atm. press.)

8. νhuman = 20Hz → 20kHz

9. Ihuman = 0 → 120 dB = 10−12→ 1 W/m2

3 Circular MotionCentripetal means towards the center of the circle

acentrip = v2

r, Fcentrip = mv2

r

T = 2πr/v (T is period of motion)

4 CollisionsI ≡ F∆t = ∆p“Elastic” = Energy is Conserved“Inlastic” = Energy is NOT Conserved“Perfectly Inlastic” = Two objects move togetherpost-collision

5 Simple Harmonic Motion

ωspring =√

km

ωpendulum =√

gL

x(t) = Acos(ωt)v(t) = −ωAsin(ωt)a(t) = −ω2Acos(ωt)ω = 2πf = 2π

T

E = 1

2mv2 + 1

2mω2x2 = Constant

6 Temp., Pressure, DensityTC = 5

9(TF − 32)

TF = 9

5TC + 32)

TK = TC + 273.15)PV = nRTPVnT

= ConstantP ≡ F/AP = P0 + ρghρ ≡ m/VFbuoy = ρfluidV gS.G.(Specific Gravity) = ρ/ρwater

P = P0 + ρfluidgh∆L = αL∆T

7 Heat TransferConduction, Convection, Radation∆T = IRR ≡

∆xkA

Rseries = R1 +R2

1

Rparallel= 1

R1

+ 1

R2

Rf ≡∆xk

= RA

8 Soundvsound,air = 331

√

1 + TC

273m/s

I ≡ P/A (Intensity)

dB = 10log(

II0

)