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Homework Help: Dam turbine power problem

  1. Jan 23, 2006 #1
    a mill requires 5000kW to operate at full capacity, produces 14tons of paper per hour, purchases electricty for $.10/kW*hr

    There is a dam 10m high that supplies water to a turbine. the river can be used only if the flow is above 50 cubic ft/sec. efficiency of generator is 75%

    how am i supposed to find "What percentage of the mill's power requirement can the dam supply?" i'm so lost
  2. jcsd
  3. Jan 23, 2006 #2
    Each second, 50 ft^3 of water transfers its kinetic energy to the mill. This energy will be equal the water's potential energy at the top of dam. So [tex]E = m g h[/tex], where m is the mass of the water (mass = density * volume), and h is the height of the damn (let's assume the water comes out at the bottom). So the power is .75 * E per second. Divide this into how much power the mill needs to get the percentage.
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