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This Appendix contains various formulas and constants that may be used throughout this text or needed to solve problems.

A.1 Constants

QuantitySymbolValue
Acceleration due to gravity at Earth’s surfacegg9.81ms29.81\,\mathrm{m\,s^{-2}}
Gravitational constantGG6.674×1011m3kg1s26.674\times 10^{-11}\,\mathrm{m^3\,kg^{-1}\,s^{-2}}
Speed of light (vacuum)cc2.998×108ms12.998\times 10^8\,\mathrm{m\,s^{-1}}
Speed of sound in air at 20C20\,{}^\circ\mathrm{C}csc_s343ms1343\,\mathrm{m\,s^{-1}}
Mass of EarthMEM_E5.98×1024kg5.98\times 10^{24}\,\mathrm{kg}
Mass of SunMSM_S1.99×1030kg1.99\times 10^{30}\,\mathrm{kg}
Mass of MoonMMM_M7.36×1022kg7.36\times 10^{22}\,\mathrm{kg}
Mean Earth orbit (astronomical unit)rEr_E1.50×1011m1.50\times 10^{11}\,\mathrm{m}
Earth radiusRER_E6.37×106m6.37\times 10^6\,\mathrm{m}
Sun radiusRSR_S6.96×108m6.96\times 10^8\,\mathrm{m}
Moon radiusRMR_M1.74×106m1.74\times 10^6\,\mathrm{m}
Planck constanthh6.63×1034Js6.63\times 10^{-34}\,\mathrm{J\,s}
Boltzmann constantkBk_B1.38×1023JK11.38\times 10^{-23}\,\mathrm{J\,K^{-1}}
Permittivity of Free Spaceϵ0\epsilon_08.854×1012CV1m18.854\times 10^{-12}\,\mathrm{C\,V^{-1}\,m^{-1}}
Permeability of Free Spaceμ0\mu_04π×107TmA14\pi\times 10^{-7}\,\mathrm{T\,m\,A^{-1}}
Elementary chargee\lvert e\rvert1.6×1019C1.6\times 10^{-19}\,\mathrm{C}
Electron massmem_e9.11×1031kg9.11\times 10^{-31}\,\mathrm{kg}
Proton massmpm_p1.67×1027kg1.67\times 10^{-27}\,\mathrm{kg}
Coulomb constantk=14πϵ0k=\frac{1}{4\pi\epsilon_0}8.99×109Nm2C28.99\times 10^9\,\mathrm{N\,m^2\,C^{-2}}

Numerical values may also be presented with prefixes. For example, km corresponds to kilometer or 1000 m.

FactorPrefixSymbolFactorPrefixSymbol
10-3millim103kilok
10-6microμ\mu106megaM
10-9nanon109gigaG
10-12picop1012teraT

A.2 Math Identities

ab=abcosθ=axbx+ayby+azbz\vec{a} \cdot \vec{b} = ab\cos \theta = a_{x}b_{x}+ a_{y}b_{y}+ a_{z}b_{z}
a×b=(aybzazby)ı^+(azbxaxbz)ȷ^+(axbyaybx)k^,a×b=absinφ\vec{a} \times \vec{b} = (a_{y}b_{z}- a_{z}b_{y})\hat{\imath} + (a_{z}b_{x}- a_{x}b_{z})\hat{\jmath} + (a_{x}b_{y}- a_{y}b_{x})\hat{k}, |\vec{a} \times \vec{b}| = ab\sin \varphi
dx(x2+a2)3/2=1a2xx2+a2,dxx2+a2=1atan1(xa),dxa2x2=sin1(xa)\int \frac{\mathrm{d}x}{(x^{2}+ a^{2})^{3/2}} = \frac{1}{a^{2}} \frac{x}{\sqrt{x^{2}+ a^{2}}}, \int \frac{\mathrm{d}x}{x^{2}+ a^{2}} = \frac{1}{a} \tan ^{-1}\bigg(\frac{x}{a} \bigg), \int \frac{\mathrm{d}x}{\sqrt{a^{2}- x^{2}}} = \sin ^{-1}\bigg(\frac{x}{a} \bigg)
Mathematical expression from source PDF page 278

sin(θ±γ)=sinθcosγ±cosθsinγ,cos(θ±γ)=cosθcosγsinθsinγ\sin (\theta \pm \gamma) = \sin \theta \cos \gamma \pm \cos \theta \sin \gamma, \cos (\theta \pm \gamma) = \cos \theta \cos \gamma \mp \sin \theta \sin \gamma

sinα±sinβ=2sin(α±β2)cos(αβ2)\sin \alpha \pm \sin \beta = 2\sin \Bigg(\frac{\alpha \pm \beta}{2} \Bigg)\cos \Bigg(\frac{\alpha \mp \beta}{2} \Bigg)
cosα+cosβ=2cos(α+β2)cos(αβ2)\cos \alpha + \cos \beta = 2\cos \Bigg(\frac{\alpha + \beta}{2} \Bigg)\cos \Bigg(\frac{\alpha - \beta}{2} \Bigg)
cosαcosβ=2sin(α+β2)sin(αβ2)\cos \alpha - \cos \beta = -2\sin \Bigg(\frac{\alpha + \beta}{2} \Bigg)\sin \Bigg(\frac{\alpha - \beta}{2} \Bigg)
ln(ab)=ln(a)+ln(b),ln(ab)=ln(a)ln(b)\ln (ab) = \ln (a) + \ln (b), \ln \bigg(\frac{a}{b} \bigg) = \ln (a) - \ln (b)

A.3 Common Approximations

See Chapter 1.6 and Appendix B for details on how functions can be approximated.

Common Taylor Series approximations for values around x0x \approx 0. Note that angles must be in units of radians for these approximations to be applicable:

sinx=xx33!+x55!x77!+cosx=1x22!+x44!x66!+ex=1+x+x22!+x33!+ln(1+x)=xx22+x33x44+11x=1+x+x2+x3+11+x=1x+x2x3+11x2=1+x2+x4+x6+11+x2=1x2+x4x6+1(1x)2=1+2x+3x2+4x3+1(1+x)2=12x+3x24x3+\begin{aligned} \sin x &= x - \frac{x^{3}}{3!} + \frac{x^{5}}{5!} - \frac{x^{7}}{7!} + \cdot \cdot \cdot \\ \cos x &= 1 - \frac{x^{2}}{2!} + \frac{x^{4}}{4!} - \frac{x^{6}}{6!} + \cdot \cdot \cdot \\ e^{x}&= 1 + x + \frac{x^{2}}{2!} + \frac{x^{3}}{3!} + \cdot \cdot \cdot \\ \ln (1 + x) &= x - \frac{x^{2}}{2} + \frac{x^{3}}{3} - \frac{x^{4}}{4} + \cdot \cdot \cdot \\ \frac{1}{1 - x} &= 1 + x + x^{2}+ x^{3}+ \cdot \cdot \cdot \\ \frac{1}{1 + x} &= 1 - x + x^{2}- x^{3}+ \cdot \cdot \cdot \\ \frac{1}{1 - x^{2}} &= 1 + x^{2}+ x^{4}+ x^{6}+ \cdot \cdot \cdot \\ \frac{1}{1 + x^{2}} &= 1 - x^{2}+ x^{4}- x^{6}+ \cdot \cdot \cdot \\ \frac{1}{(1 - x)^{2}} &= 1 + 2x + 3x^{2}+ 4x^{3}+ \cdot \cdot \cdot \\ \frac{1}{(1 + x)^{2}} &= 1 - 2x + 3x^{2}- 4x^{3}+ \cdot \cdot \cdot \end{aligned}
11x=1+x2+3x28+5x316+11+x=1x2+3x285x316+\begin{aligned} \frac{1}{\sqrt{1 - x}} &= 1 + \frac{x}{2} + \frac{3x^{2}}{8} + \frac{5x^{3}}{16} + \cdot \cdot \cdot \\ \frac{1}{\sqrt{1 + x}} &= 1 - \frac{x}{2} + \frac{3x^{2}}{8} - \frac{5x^{3}}{16} + \cdot \cdot \cdot \end{aligned}
11x2=1+x22+3x48+5x616+11+x2=1x22+3x485x616+\frac{1}{\sqrt{1 - x^{2}}} = 1 + \frac{x^{2}}{2} + \frac{3x^{4}}{8} + \frac{5x^{6}}{16} + \cdot \cdot \cdot \frac{1}{\sqrt{1 + x^{2}}} = 1 - \frac{x^{2}}{2} + \frac{3x^{4}}{8} - \frac{5x^{6}}{16} + \cdot \cdot \cdot

A.4 Moment of Inertia

The Moment of Inertia, II, represents how the mass of a system is distributed as a function of position and describes how efficiently the system rotates. Here is a chart of basic shapes and their moments of inertia. For information on how to calculate Moments of Inertia see Section 7.2.2.

Illustration from source PDF page 279

A.5 Vector Differential Operators

This section gives the full coordinate transformations for the gradient, divergence, and curl in 3-D. The following is a brief explanation of those coordinate transformations.

A.5.1 General Coordinates

In general, consider a 3-D coordinate system c1,c2c_{1}, c_{2}, and c3c_{3} with orthogonal unit vectors defined as e^1,e^2\hat{e}_{1}, \hat{e}_{2}, and e^3\hat{e}_{3}. Note that c1,c2c_{1}, c_{2}, and c3c_{3} are merely stand-ins for x,y,zx,y,z or r,θ,φr,\theta,\varphi.

In this general 3-D coordinate system, a line element would be

ds=h1dc1,h2dc2,h3dc3\mathrm{d}s = \langle h_{1}\mathrm{d}c_{1},h_{2}\mathrm{d}c_{2},h_{3}\mathrm{d}c_{3}\rangle

where h1,h2h_{1}, h_{2}, and h3h_{3} are scale factors that may need to be applied to each coordinate (the value of these scale factors depends on the coordinate transformation - more on this below).

Because of these scale factors, the gradient, divergence, and curl transformations will be a bit different in each coordinate system. In the general form, these functions are:

The gradient of a function ff is then defined as:

f=(1h1fc1)e^1+(1h2fc2)e^2+(1h3fc3)e^3\vec{\nabla}f = \Bigg(\frac{1}{h_{1}} \frac{\partial f}{\partial c_{1}} \Bigg)\hat{e}_{1}+ \Bigg(\frac{1}{h_{2}} \frac{\partial f}{\partial c_{2}} \Bigg)\hat{e}_{2}+ \Bigg(\frac{1}{h_{3}} \frac{\partial f}{\partial c_{3}} \Bigg)\hat{e}_{3}

The divergence of a vector A\vec{A} is:

A=1h1h2h3[c1(h2h3A1)+c2(h1h3A2)+c3(h1h2A3)]\vec{\nabla} \cdot \vec{A} = \frac{1}{h_{1}h_{2}h_{3}} \Bigg[\frac{\partial}{\partial c_{1}} (h_{2}h_{3}A_{1}) + \frac{\partial}{\partial c_{2}} (h_{1}h_{3}A_{2}) + \frac{\partial}{\partial c_{3}} (h_{1}h_{2}A_{3})\Bigg]

and the curl of a vector A\vec{A} is:

×A=1h1h2h3h1e^1h2e^2h3e^3c1c2c3h1A1h2A2h3A3\vec{\nabla} \times \vec{A} = \frac{1}{h_{1}h_{2}h_{3}} \begin{vmatrix} h_{1}\hat{e}_{1} & h_{2}\hat{e}_{2} & h_{3}\hat{e}_{3} \\ \dfrac{\partial}{\partial c_{1}} & \dfrac{\partial}{\partial c_{2}} & \dfrac{\partial}{\partial c_{3}} \\ h_{1}A_{1} & h_{2}A_{2} & h_{3}A_{3} \end{vmatrix}

A.5.2 Cartesian Coordinates

In the Cartesian system, we have c1=x,c2=yc_{1}= x, c_{2}= y, and c3=zc_{3}= z and h1=1,h2h_{1}= 1, h_{2} = 1, and h3h_{3} = 1. As a result, we have the following for Cartesian Coordinates:

f=fxx^+fyy^+fzz^\vec{\nabla}f = \frac{\partial f}{\partial x} \hat{x} + \frac{\partial f}{\partial y} \hat{y} + \frac{\partial f}{\partial z} \hat{z}
A=[x(A1)+y(A2)+z(A3)]\vec{\nabla} \cdot \vec{A} = \Bigg[\frac{\partial}{\partial x} (A_{1}) + \frac{\partial}{\partial y} (A_{2}) + \frac{\partial}{\partial z} (A_{3})\Bigg]
×A=x^y^z^xyzA1A2A3\vec{\nabla} \times \vec{A} = \begin{vmatrix} \hat{x} & \hat{y} & \hat{z} \\ \dfrac{\partial}{\partial x} & \dfrac{\partial}{\partial y} & \dfrac{\partial}{\partial z} \\ A_{1} & A_{2} & A_{3} \end{vmatrix}

where x^\hat{x} is used for ı^,y^\hat{\imath}, \hat{y} is used for ȷ^\hat{\jmath} , and z^\hat{z} is used for k^\hat{k} .

A.5.3 Cylindrical Coordinates

In cylindrical coordinates, c1=r,c2=θc_{1}= r, c_{2}= \theta, and c3=zc_{3}= z, where

x=rcosφy=rsinφ\begin{aligned} x &= r\cos \varphi \\ y &= r\sin \varphi \end{aligned}

For cylindrical coordinates, h1=1,h2=rh_{1}= 1, h_{2}= r, and h3h_{3} = 1. Note, these terms should look familiar. That is, for a cylinder, a tiny section of volume is given by:

dV=rdrdθdzdV = r \mathrm{d}r\mathrm{d}\theta \mathrm{d}z

Based on the above, we get the following for cylindrical coordinates.

f=(fr)r^+(1rfθ)θ^+(fz)z^\vec{\nabla}f = \Bigg(\frac{\partial f}{\partial r} \Bigg)\hat{r} + \Bigg(\frac{1}{r} \frac{\partial f}{\partial \theta} \Bigg)\hat{\theta} + \Bigg(\frac{\partial f}{\partial z} \Bigg)\hat{z}
A=1r[r(rA1)+θ(A2)+z(rA3)]\vec{\nabla} \cdot \vec{A} = \frac{1}{r} \Bigg[\frac{\partial}{\partial r} (rA_{1}) + \frac{\partial}{\partial \theta} (A_{2}) + \frac{\partial}{\partial z} (rA_{3})\Bigg]
×A=1rr^rθ^z^rθzA1rA2A3\vec{\nabla} \times \vec{A} = \frac{1}{r} \begin{vmatrix} \hat{r} & r\hat{\theta} & \hat{z} \\ \dfrac{\partial}{\partial r} & \dfrac{\partial}{\partial \theta} & \dfrac{\partial}{\partial z} \\ A_{1} & rA_{2} & A_{3} \end{vmatrix}

A.5.4 Spherical Coordinates

In spherical coordinates, c1=r,c2=θc_{1}= r, c_{2}= \theta, and c3=φc_{3}= \varphi, where

x=rsinθcosφy=rsinθsinφz=rcosθ\begin{aligned} x &= r\sin \theta \cos \varphi \\ y &= r\sin \theta \sin \varphi \\ z &= r\cos \theta \end{aligned}

For spherical coordinates, h1=1,h2=rh_{1}= 1, h_{2}= r, and h3=rsinθh_{3}= r\sin \theta. Note, these terms should look familiar. That is, for a sphere, a tiny section of volume is given by:

dV=r2sinθdrdθdφdV = r^{2}\sin \theta \mathrm{d}r\mathrm{d}\theta \mathrm{d}\varphi

Based on the above, we get the following for spherical coordinates.

f=(fr)r^+(1rfθ)θ^+(1rsinθfφ)φ^\vec{\nabla}f = \Bigg(\frac{\partial f}{\partial r} \Bigg)\hat{r} + \Bigg(\frac{1}{r} \frac{\partial f}{\partial \theta} \Bigg)\hat{\theta} + \Bigg(\frac{1}{r\sin \theta} \frac{\partial f}{\partial \varphi} \Bigg)\hat{\varphi}
A=1r2sinθ[r(r2sinθA1)+θ(rsinθA2)+φ(rA3)]\vec{\nabla} \cdot \vec{A} = \frac{1}{r^{2}\sin \theta} \Bigg[\frac{\partial}{\partial r} (r^{2}\sin \theta A_{1}) + \frac{\partial}{\partial \theta} (r\sin \theta A_{2}) + \frac{\partial}{\partial \varphi} (rA_{3})\Bigg]
×A=1r2sinθr^rθ^rsinθφ^rθφA1rA2rsinθA3\vec{\nabla} \times \vec{A} = \frac{1}{r^{2}\sin \theta} \begin{vmatrix} \hat{r} & r\hat{\theta} & r\sin\theta\,\hat{\varphi} \\ \dfrac{\partial}{\partial r} & \dfrac{\partial}{\partial \theta} & \dfrac{\partial}{\partial \varphi} \\ A_{1} & rA_{2} & r\sin\theta\,A_{3} \end{vmatrix}