\documentclass{IEEEtran} \usepackage{amsmath} \title{ME for ECEs Equation Sheet} \begin{document} \maketitle \section{Vectors} $$\vec{v}_R = \sum v_x \hat{x} + \sum v_y \hat{y} + \sum v_z \hat{z}$$ $$\|\vec{v}\| = \sqrt{v_x^2 + v_y^2 + v_z^2}$$ $$\begin{align} \vec{u} \cdot \vec{v} &= \|\vec{u}\| \|\vec{v}\| \cos(\theta) \\ &= (u_x v_x) + (u_y v_y) + (u_z v_z) \end{align}$$ $$\begin{align} \vec{u} \times \vec{v} &= \begin{vmatrix} \hat{x} & \hat{y} & \hat{z} \\ u_x & u_y & u_z \\ v_x & v_y & v_z \end{vmatrix} \\ &= (u_y v_z - u_z v_y)\hat{x} - (u_x v_z - u_z v_x)\hat{y} + (u_x v_y - u_y v_x)\hat{z} \end{align}$$ \section{Statics} $$\vec{F} = m \vec{a}$$ $$\vec{M} = \vec{r} \times \vec{F}$$ $$\vec{r} = \vec{s}_f - \vec{s}_0$$ $$\sum F = 0$$ $$\sum M = 0$$ \section{Dynamics} \subsection{Kinematic Equations} $$\vec{s}_f - \vec{s}_0 = \vec{v}_0 t + {1\over2} \vec{a} t^2$$ $$\vec{v}_f^2 = \vec{v}_0^2 + 2 \vec{a} \cdot (\vec{s}_f - \vec{s}_0)$$ $$\vec{v}_f = \vec{v}_0 + \vec{a}t$$ $$\vec{s}_f = \vec{s}_0 + \vec{v}t$$ \subsection{Projectile Motion} $$\vec{g} = -9.81\hat{y}\left[{\text{m} \over \text{s}^2}\right] = -32.2\hat{y} \left[{ \text{ft} \over \text{s}^2}\right]$$ Without air resistance: $$v_{x_0} = v_{x_f}$$ \section{Heat Transfer} \subsection{Conduction} $$q_x'' = k {dT \over dx}$$ $${dT \over dx} = {T_2 - T_1 \over L}$$ $$q_x = q_x'' A$$ Where: \begin{itemize} \item[$q_x''$] is heat flux \item[$q_x$] is heat rate \item[$T$] is temperature \item[$L$] is length \item[$A$] is the contact area \end{itemize} \subsection{Convection} $$q'' = hA(T_s - T_\infty)$$ Where: \begin{itemize} \item[$h$] is the heat transfer coefficient \item[$A$] is the contact area between the surface and the fluid \item[$T_s$] is the surface temperature \item[$T_\infty$] is the fluid temperature very far away from the surface \end{itemize} \subsection{Radiation} $$q_\text{ideal}'' = \sigma T_s^4$$ $$q_\text{real}'' = \varepsilon \sigma T_s^4$$ Where: \begin{itemize} \item[$T_s$] is the absolute temperature \item[$\sigma$] is the Stefan-Boltzmann constant \item[$\varepsilon$] is the emissivity \end{itemize} \section{Fluids} \noindent Pascal's Law: $${F_1 \over A_1} = {F_2 \over A_2}$$ Density: $$\rho = {m \over v}$$ Specific Weight: $$\gamma = {mg \over v} = \rho g$$ Pressure in a fluid: $$P_2 = P_1 + \rho g z$$ Bernoulli Equation: $$p_1 + {1\over2}\rho v_1^2 + \rho g h_1 = p_2 + {1\over2}\rho v_2^2 + \rho g h_2$$ Fluid Velocity Between Plates: $${U \over b} = {u \over y}$$ Where: \begin{itemize} \item[$U$] is the velocity of the moving plate \item[$b$] is the distance between the plates \item[$u$] is the velocity of the fluid at between the plates at some distance above the stationary plate \item[$y$] is the distance above the stationary plate. \end{itemize} Continuity Equation $$A_1 v_1 \Delta t = A_2 v_2 \Delta t$$ $$\dot{m} = \rho_1 A_1 v_1 = \rho_2 A_2 v_2$$ \section{Gears} $$N = P d$$ $$N = {d \over m}$$ $$c = {d_1 + d_2 \over 2} = {N_1 + N_2 \over 2 P} = {(N_1 + N_2) m \over 2}$$ Where: \begin{itemize} \item[$N$] is the number of teeth \item[$d$] is the pitch diameter \item[$c$] is the center distance \item[$P$] is the diametral pitch (Customary) \item[$m$] is the module (SI) \end{itemize} \noindent Gear Ratio: $$R = {T_2 \over T_1} = {N_2 \over N_1} = {d_2 \over d_1} = {\omega_1 \over \omega_2}$$ $$\omega = {\pi \over 30}\text{RPM}$$ \noindent Big Gear to Small Gear: \begin{itemize} \item Speed increases \item Torque decreases \end{itemize} \noindent Small Gear to Big Gear: \begin{itemize} \item Speed decreases \item Torque increases \end{itemize} \noindent Power: $$P = \omega T$$ If no power losses: $$P_\text{in} = P_\text{out}$$ $$\omega_1 T_1 = \omega_2 T_2$$ \end{document}