PIRATES!!!!!!

You are out fishing for salmon, and your Salmon fishing vessel gets (commandeered) by PIRATES!  They make you and your crewmen walk the plank, as seen in the diagram below. 


The plank that the pirates demand your crewmen walk is beam with a mass (m) supported by a massless cord.  The plank is in static equilibrium, but your crewman is curious to know the tension in the cord supporting the plank and the forces action on the hinge (star).  Even though you think this is not the time to discuss physics, you decide to create a diversion by explaining your conundrum to your crewmen and the pirates.                 
                                     

"Becasue we are in static equilibrium, the sum of the forces in the Y-direction (towards the sky and ocean floor) and in the X-direction (from bow to stern), and the sum of the torques are all equal to zero."  You explain to your unimpressed guests and crewmen that there are tension forces and forces at the plank hinge that act in the X- and Y- directions.  "In the Y-direction, your weight, the weight of the plank, the Y-component of tension, and the Y-component of the hinge force all add up to zero.  The only forces in the X-direction," you exclaim, "are the X-components of the tension and hinge forces".  "As for the sum of the torques," you say, thinking you'll really show up these pirates, "the forces at the hinge don't matter!"
Puzzled, they tell you you're wrong.  Laughing, you tell them, "It's true, because the torque is measured around the hinge, or pivot, point, the only relevant torques are the Y-component of the cord tension, the mass of the beam, and us (the harmless crew that really deserves their ship back).  And, ...and the sum of the torques crossed with the distance from the hinge gives us the tension in the cord!"  Your crewman catches on to your distraction technique, and concludes that we can determine the forces acting on the hinge from our discovery of the tension in the cord...


                  You confuse the pirates with your physics genius (you are the captain afterall),
and they exit your vessel!!!





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