Calculating Internal Energy at Victoria Falls

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To calculate the internal energy produced by water falling at Victoria Falls, one must consider the potential energy (PE) from the height of the fall, which is approximately 33,006.7 J for 1 kg of water. The kinetic energy (KE) at the bottom is not directly given, but it is suggested that it transforms into internal energy upon impact. The total internal energy is derived from the conversion of mechanical energy (PE and KE) into internal energy, emphasizing the distinction between macroscopic and microscopic energy forms. The discussion highlights that while calculating KE is not necessary for determining internal energy, understanding the energy transformation during the fall is crucial. Ultimately, the focus is on the conversion of mechanical energy into internal energy as the water crashes at the bottom.
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Homework Statement


The water passing over Victoria Falls, located along the Zambezi River on the border of Zimbabwe and Zambia, drops about 105 m. How much internal energy is produced per kg as a result of the fall?


Homework Equations



PE=mgh
KE=mc * deltaT

The Attempt at a Solution



PE=33.0067 u * 9.81 * 105= 33998.55134 J
KE= ??

How do I calculate KE if they don't give me the temp of the water?
To get the IE, do I just add KE and PE?

Thanks
 
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I don't see anyone asking you to caculate the rise in temperature (though you could). All you need to figure out is the increase in internal energy. Calculate the amount of mechanical energy converted to internal energy after the water falls. (Hint: What happens to the kinetic energy when the water crashes at the bottom of the falls.)
 
Doc Al said:
I don't see anyone asking you to caculate the rise in temperature (though you could). All you need to figure out is the increase in internal energy. Calculate the amount of mechanical energy converted to internal energy after the water falls. (Hint: What happens to the kinetic energy when the water crashes at the bottom of the falls.)

Internal energy is the total energy (the sum of kinetic and potential energies) attributed to the particles of matter.

So wouldn't I have to calculate PE and KE, then add their values to get the total internal energy?
 
mikefitz said:
Internal energy is the total energy (the sum of kinetic and potential energies) attributed to the particles of matter.
I think you need to be more precise and distinguish internal energy from macroscopic mechanical energy. Read this: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html"

So wouldn't I have to calculate PE and KE, then add their values to get the total internal energy?
When the water falls and crashes into the rocks (or still water) its ordered, macroscopic KE is transformed into disordered microscopic internal energy. How much KE does 1 kg of water have at the bottom of the falls?
 
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Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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