Water from a stream is used to drive a water wheel. The stream provides 6000kg of water per minute to the wheel. The water falls a vertical height of 5 meters.
Show that the maximum power available to the wheel from the water is 5000W. Halp?
okay, I admit it, I don't know about this stuff but
I just googled "what is a watt" and I was told that
1W = 1Kg*m^2 / s^3
So I am just going to use the units and there is a reasonable chance that I will get the right answer.
You have 6000kg/min = 6000/60 Kg/sec = 100Kg/sec
You have gravity which is 9.8m/s^2
You have 5m
Kg/sec * m/s^2 * m = Kg*m^2/sec^3 Well that is the units that I want
100 * 9.8 * 5 = 4900W
If I had rounded gravity off to 10m/s^2 I would have 5000W
This is the maximum because some of the energy will be lost. (eg noise I think but again I don't really know what I am tallking about)
The motto of this story is:
Always use the units to help you
+118653 
