![[click to enlarge] [click to enlarge]](logos/LSUMathContestTShirt2019.png)  | 
                                  This years contest logo was developed by Professor Padmanabhan Sundar of the LSU Mathematics Department.   The logo design gives a three-dimensional picture of collision dynamics of two colliding particles that travel in a vacuum. 
Here, \(u\) and \(v\) denote pre-collision velocities, and \(u^*\) and \(v^*\), post-collision velocities. On account of 
conservation of momentum and energy, they lie on a sphere with center at \(\frac{(u + v)}{2}\) and diameter equal to \( |v - u| \). 
One may take \(u\) as the south pole and \(v\) as the north pole. 
While the  conservation laws provide us with four equations, \( (u^*, v^*) \) is six dimensional. Hence, in 
writing \(u^*\) and \(v^*\) as  functions of \(u\) and \(v\), one needs two parameters. If the unit vector in the direction of 
\(v^* - v\) is called \(n\), then it enables one to write  \(v^*\) in terms of \(u\), \(v\) and \(n\). In spherical coordinates, \(n\) is 
written as a function of \(\theta\) and \(\xi\) where \(\theta\) is the co-lattitude and \(\xi\)  is the meridian for the velocity \(v^*\).  
 
                              
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