Not even sure where to start with this one :\

Water flows over a section of Niagara Falls at

a rate of 1.4 x 10^6 kg/s and falls 59 m.

The acceleration of gravity is 9.8 m/s^2.

What is the power wasted by the waterfall?

Answer in units of W.

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- Mar 5th 2008, 11:23 AMvesperkaPhysics - Power
Not even sure where to start with this one :\

Water flows over a section of Niagara Falls at

a rate of 1.4 x 10^6 kg/s and falls 59 m.

The acceleration of gravity is 9.8 m/s^2.

What is the power wasted by the waterfall?

Answer in units of W. - Mar 5th 2008, 01:37 PMJaneBennet
In one second, $\displaystyle 1.4\times10^6\ \textrm{kg}$ of water passes through that particular section. The work done by gravity on this mass of water as it falls through $\displaystyle 59\ \textrm{m}$ is $\displaystyle 1.4\times10^6\times9.8\times59=8.0948\times10^8\ \textrm{J}$. This is the amount of energy “wasted” per second; hence the power wasted by the waterfall is $\displaystyle 8.0948\times10^8\ \textrm{W}$.

- Mar 5th 2008, 03:38 PMvesperka
Thanks man. I haven't worked with power before but I'm starting to see how the whole thinking process works now, thanks a bunch :D