ElectricPavlov

A was 56.5km^2 and h 8m.

Here is the conversion:   56.5 km^2 = 56.5 x 10^6 m^2 = 5.65 x 10^7 m^2

This will reduce your answer by a factor of 10.....

The remaining question is      Is A really  56.5 km^2 ?    

Yes....I saw after I posted that the 64 was 8^2 and the other 8 was an exponent.....

Perhaps Wikipedia has the wrong answer !!   Perhaps look somewhere else...they may have made a typo ......

E=1/2 Apgh^2    from

http://hydropower-tidalpower.blogspot.com/2009/07/energy-calculations_07.html

Which has a sample calc.....which will step you through your calculations to see where you might have erred

  your '8' for tidal height....is that in meters? (should be...not in feet)

Did you divide by the seconds in a day (86400)   /  Did you multiply by 2 (tides per day) as in the example????

Let me know !     G'Day !!

I THINK this means 'solve for 's' '

v^2 - u^2 = 2 as

(v^2-u^2)/(2a) = s

.5  x  64  x  1025   x   5.65 x10^8    x  8^2   x   9.8 = 116232704 x 10^8      

                      kg/m^3      m^2                m^2         m/s^2   =   kg  m^2/s^2    (correct units?)

where did 64  come from?   8 should be squared according to your equation......

Can you answer these questions for me.....   and where did you GET this eqution?

I'll see if I can help further....

Nice job completing the puzzle Hecticar !     The PROBLEM wasn't that difficult, but the erroneous presentation (which you figured out) was !        Keep up the good work !!

An old saying : "Life is what you make it"

Many of us on the forum (I think including YOU) had this discussion a few months ago and decided this representation was rather ambiguous, but most agreed it is

[(8.4 x 10^7)/4] x 10^12     so your first solution is the one considered correct by most of us and most calculators too......     use brackets to be clear !!!

10^2  is 1 with two zeros after it   (10 x 10) = 100

1 / (-3/4 X - 3/4 x -3/4 x -3/4)  =  1 /  (81/256) = 256/81 = 3 13/81