Module 2 Equations and Graphs Graph: The three dimensional graph, with three axes, labeled x, y, and z, shows a curved line running through it, which represents the trajectory of a particle. There is a vector labeled capital X as a function of time, running from the origin (0,0,0), to a point on the curved line. The point that the vector ends at is signified by a big red dot, which represents the particle at a given time in history. Modification to graph: A vector labeled V as a function of time, lowercase t, which represents the velocity of the particle, extends from the red dot, the particle, outwards on a path that is tangent to the curved trajectory of that particle. Equation: Capital V as a function of time, which represents particle velocity, equals the derivative of capital X as a function of time, which represents the vector from the origin to the particle along its trajectory. Equation: X superscript n, representing the position of the nth particle, equals capital X superscript lowercase n in parenthesis, all as a function of time, lowercase t. Also, capital V superscript lowercase n in parenthesis, the velocity of the nth particle, equals capital V superscript lowercase n, all as a function of time, lowercase t. Lowercase n is an integer. Equation: Capital X equals capital X as a function of time, lowercase t, and lowercase n, an integer. Capital V equals capital V as a function of time, lowercase t, and lowercase n, and integer. Equation: Capital X equals capital X as a function of time, lowercase t, lowercase a, lowercase b, and lowercase c, where lowercase a, b, and c must span the space. Equation: The material coordinates lowercase a, lowercase b, lowercase c equal capital X subscript zero, which equals capital X as a function of 0 and capital X subscript 0. Graph: This three dimensional graph has three axes, the x, y, and z. It has a curved line running through it, depicting the trajectory of a particle. There is a vector traveling from the origin to the particle’s current position on it’s trajectory. This vector is labeled capital bold-faced X as a function of time, lowercase t. There is another vector traveling from the origin of the graph to the beginning of the trajectory, at time, lowercase t, equal to zero. This vector is labeled capital bold-faced capital X subscript zero. Diagram: This picture depicts a narrow tube of some kind, with a measuring device stuck into it that resembles a right-angle ruler. An arrow is used to show that fluid is passing through the tube in the direction of the arrow, past the measurement device. Diagram: This diagram shows a device that bends the fluid as the fluid moves past, while at the same time measuring the fluid particles. A dotted box surrounds the fluid that is in the scope of the device’s measurements. Variable: The partial derivative of capital theta with respect to time, subscript lowercase x subscript zero. Equation: (All derivatives are done with respect to time, lowercase t, unless otherwise noted) The partial derivative of capital theta subscript lowercase x equals the partial derivative of lowercase theta subscript lowercase x times the partial derivative of time subscript lowercase x subscript zero plus the partial derivative of lowercase theta with respect to lowercase x subscript lowercase i, with the whole derivative having a subscript lowercase t, times the partial derivative of x with a subscript i, with a subscript for the whole partial derivative of x subscript zero. Equation: The partial derivative of time with respect to time subscript one. The partial derivative of lowercase x subscript lowercase i with respect to lowercase t with a subscript of lowercase x subscript zero equals partial derivative of uppercase X subscript lowercase i with respect to lowercase t with a subscript of lowercase x subscript zero, equals capital V subscript lowercase i as a function of capital X subscript zero and time. Equation modified (All derivatives are with respect to time, unless otherwise stated): The partial derivative of capital theta subscript lowercase x subscript zero equals the partial derivative of lowercase theta subscript lowercase x, plus lowercase v subscript lowercase i as a function of bold lowercase x and time, lowercase t, times the partial derivative of lowercase theta with respect to lowercase x subscript lowercase i, with the whole derivative having a subscript of lowercase t. Equation modification (All derivatives are with respect to time, unless otherwise stated): The partial derivative of capital theta equals the partial derivative of lowercase theta plus lowercase v subscript lowercase i times the partial derivative of lowercase theta with respect to lowercase x subscript lowercase i. The partial derivative of capital theta equals the partial derivative of lowercase theta plus lowercase bold v dot the gradient operating on theta. Equation modification: The partial derivative of capital theta in the previous equation is replaced with capital D lowercase theta with respect to lowercase t.