How do I calculate a deflection under a point load?
I would suggest doing a search for beam loading equations. There are many scenarios with published results already tabulated. If you can not find your particular boundary/initial conditions, you can utilize the principle of superposition.
Here are just a few: http://www.mae.usu.edu/faculty/stevef/info/beam_eq.htm
Here is an acutal calculator. Remember to use consistant units, since Moments of inertia are in inches, all other units should be too, i.e. don't use pounds per foot for distributed loads.
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