Physics of Dipnetting :: physics dip net netting

The Physics of Dip lollyIntroduction to Dip NettingDip netting for pink-orange in the Copper River is a throne of fun but is also a lot of work. During the summer months salmon will leave their home in the ocean and travel upstream in the Copper River to spawn in its many tributaries. Near the piffling town of Chitna the Copper River flows through a narrow send wordyon which greatly increases the speed of the river. This makes it harder for the salmon to swim upstream. However the canyon also creates natural covering eddies near the shore in which the river will actually flow the black eye direction. This is good and bad news for the salmon. Good news because the back eddies atomic number 18 flowing the direction the salmon want to go which makes their trip a lot easier. And bad news (from the salmons point of view of course), it makes the salmon easier to date because the water is flowing the ideal direction for dip netters as shown in the pictures below.Notice that the bac k eddie makes it unfeignedly easy for the dip netter. If there was no back eddie the current would push the net the other direction, which makes dip netting a lot harder.The PhysicsThe physics of dip netting is really quite simple. All a person has to do is find a back eddie with a nice constant current and hold the net underwater in the hopes a salmon will swim into it. The physics then becomes a static equilibrium problem which means that none of the parts are moving in any way any in translation or in rotation (applies only to lengthiness frame used) (Halliday 307). This is illustrated in the picture below.The dip net rod cell can be compared to a lever of class 1 and the lever ruler can be applied, similar to the applet at http//www.walter-fendt.de/ph11e/lever.htm. As stated in the applet from the Contemporary College Physics Simulation Library a lever is in balance if the positive left side torque is equal to the total right side torque. Applying that statement to the pic ture above the person must apply a much greater force on the pole in order to maintain torque equilibrium because the duration from the thole point is much less than the distance from the force of the current to the fall point. This can be expressed mathematically.F1D1 = F2D2. (where F is each force, and D is the distance each force is from the pivot point)