# OpenStax College Physics/Formulas (master)

##### Introduction

Introduction  ◊hello

##### Kinematics

Kinematics  ◊hello  =====Two-Dimensional Kinematics=====Two-Dimensional Kinematics  ◊hello  =====Dynamics: Force and Newton's Laws of Motion=====Dynamics: Force and Newton's Laws of Motion  ◊hello  =====Further Applications of Newton's Laws: Friction, Drag, and Elasticity=====Further Applications of Newton's Laws: Friction, Drag, and Elasticity  ◊hello  =====Uniform Circular Motion and Gravitation=====Uniform Circular Motion and Gravitation  ◊hello  =====Work, Energy, and Energy Resources=====Work, Energy, and Energy Resources  ◊hello  =====Linear Momentum and Collisions=====Linear Momentum and Collisions  ◊hello  =====Statics and Torque=====Statics and Torque  ◊hello  =====Rotational Motion and Angular Momentum=====Rotational Motion and Angular Momentum  ◊hello  =====Fluid Statics=====Fluid Statics  ◊hello  =====Fluid Dynamics and Its Biological and Medical Applications=====Fluid Dynamics and Its Biological and Medical Applications  ◊hello  =====Temperature, Kinetic Theory, and the Gas Laws=====Temperature, Kinetic Theory, and the Gas Laws  ◊hello  =====Heat and Heat Transfer Methods=====Heat and Heat Transfer Methods  ◊hello  =====Thermodynamics=====Thermodynamics  ◊hello

##### Oscillatory Motion and Waves

16. Oscillatory Motion and Waves  $F=-kx$ (Hooke's law)    $PE_{el}={\tfrac {1}{2}}kx^{2}$ (Spring energy)   $fT=1$ (frequency-period)   $\omega \equiv 2\pi /T={\sqrt {k/m}}{\text{ or }}{\sqrt {g/L}}$ (mass/spring or simple pendulum)   $x=X\cos(\omega t),$ $v=-\omega X\sin(\omega t),$ $a=-\omega ^{2}X\cos(\omega t)$ (simple harmonic motion)   $f\lambda =v_{w}$ (wave speed)   $f_{B}=|f_{1}-f_{2}|$ (beat frequency)

##### Physics of Hearing

17. Physics of Hearing   $v_{w}=f\lambda \approx ({\text{331m/s}}){\sqrt {T/{\text{273K}}}}$ (sound speed)   $I=P/A=(\Delta p)^{2}/(2\rho v_{w})$ (sound intensity)   $\beta {\text{(dB)}}=10\log _{10}(I/I_{0})$ (I0 = 10-12W/m2 is the hearing threshold level)   $f_{obs}=f_{s}\left({\frac {v_{w}}{v_{w}\pm v_{s}}}\right)$ (+/- for motion (away/towards) stationary observer)   $f_{obs}=f_{s}\left({\frac {v_{w}\pm v_{obs}}{v_{w}}}\right)$ (+/- for motion (towards/away from stationary source)   $f_{n}=n{\frac {v_{w}}{4L}}$ $n=1,3,5...$ (one end closed)   $f_{n}=n{\frac {v_{w}}{2L}}$ $n=1,2,3...$ (both ends open)   $a=(Z_{2}-Z_{1})^{2}/(Z_{1}+Z_{2})^{2}$ (intensity reflection coefficient with acoustical impedance $Z=\rho v_{w}$ )

##### Electric Charge and Electric Field

18. Electric Charge and Electric Field  e≈1.6 x 10−19 C (fundamental charge)   $F=k{\frac {|q_{1}q_{2}|}{r^{2}}}$ (Coulomb's law with k ≈8.99x109 N m2 C−2)   ${\vec {F}}=q{\vec {E}}$ (Force law with E =kq/r2 for the electric field due to a point charge)

##### Electric Potential and Electric Field

19. Electric Potential and Electric Field   $\Delta {\text{PE}}=q\Delta V=q(V_{B}-V_{A})$ (potential energy for moving from A to B)   $1eV\approx 1.6\times 10^{-16}{\text{ Joules}}$ (unit conversion)   $E=-\Delta V/\Delta s$ (change in electric potential for small step parallel to electric field)   $V=kQ/r$ (point charge)   $Q=CV$ (capacitor charge)    $C=\varepsilon _{0}A/d$ (parallel plate with ε0 = 8.85×10−12F/m)   ε=κε0 (dielectric correction)   ${\frac {1}{C_{S}}}={\frac {1}{C_{1}}}+{\frac {1}{C_{2}}}+{\frac {1}{C_{3}}}+\dots$ (series)   $C_{p}=C_{1}+C_{2}+C_{3}+\dots$ (parallel)   $E_{cap}={\tfrac {1}{2}}QV={\tfrac {1}{2}}CV^{2}=Q^{2}/(2C)$ (stored energy)

##### Electric Current, Resistance, and Ohm's Law

20. Electric Current, Resistance, and Ohm's Law   $I=\Delta Q/\Delta t$ (current:(1A≡1C/s)   $I=nqAv_{d}$ (current and drift velocity)   $V=IR$ (Ohm's law: 1Ω=1V/A)   $R=\rho L/A$ (resistivity and resistance)   $\rho =\rho _{0}+\alpha \Delta T$ (temperature coefficient)   $P=IV=I^{2}R=V^{2}/R$ (power as energy/time)   $P_{\text{ave}}=I_{\text{rms}}V_{\text{rms}}=I_{\text{rms}}^{2}R=V_{\text{rms}}^{2}/R$ ([alternating current)  $X_{\text{rms}}={\tfrac {1}{\sqrt {2}}}X_{0}$ (rms and peak value) $X(t)=X_{0}\sin(2\pi ft)$ )

##### Circuits and DC Instruments

21. Circuits and DC Instruments    $R_{s}=R_{1}+R_{2}+R_{3}+\ldots$ (series)    $R_{eq}^{-1}=$ $R_{1}^{-1}+R_{2}^{-1}+R_{3}^{-1}+\ldots$ (parallel)   $V_{\text{terminal}}={\text{emf}}-Ir$ (terminal voltage, emf, internal resistance)    $\Sigma I_{\text{out}}=\Sigma I_{\text{in}}$ and $\Sigma \Delta V=0$ (Kirchhoff's rules: $\Delta V>0$ if path from − to + voltage or opposite current through resistor    $\tau =RC$ (RC time): $V={\text{emf}}\,(1-e^{-t/RC})$ (charging)   $V={\text{emf}}\,e^{-t/RC}$ (discharging)

hello

Magnetism   hi