String theory

# String theory

Nowadays as there is shortage of electricity in all over the slow countries i...

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String theory discussion

asim4jan
07/08/10
Nowadays as there is shortage of electricity in all over the slow countries in the world our aim is to produce elctricity from cheaper materials like water etc my question is about the power crises in pakistan as we see in news that there is very bad loadshedding all over the country
if we make a big water tank about some height from the earth and store water on it now by means of pipes these huge amount of water is then flow out from the tank and below it we have installed a big electric generater which generate the power now when the water after from the generater comes into another small area now at this instant some water pump again send the water again to the tank above......... the power produced by the generator will be half used by the water pumps and remaining will be send to homes near by it then say me where is the probelom by creating such type of self electric generating plant???? if there is any suggestion inform me thanks bye bye

yuvrajhanspal
09/06/10
replied to: asim4jan
Hi

what you are saying is that you are trying to construct a perpetual motion machine with half output going as input and the rest half being consumed elsewhere(out of the "water + generator" system). How, pray tell me , can you construct without energy loss in friction? or heat? or transmission loss? and think, how is it possible to take the same water up the same height it came while spending the half energy?

think of it this way

water height above generator = h

energy of m kgs (approx m litres) water = m.g.h

so if the full energy is converted to electricity, how much energy do we have? E(produced)

E(produced) = m*g*h

and energy spent on taking same m kgs back that same height(h) [according to you] = m.g.h/2 or 0.5*m*g*h

so think how high can same water go? let the new height be h'

h' = E(spent)/(m*g)
or h' = 0.5*m*g*h/m*g
so h' = 0.5 h

so how can u reach the same height?

PLEASE bear in mind that i have ignored all the "real life energy losses" like friction/heat/transmission losses. these losses, though might be a small amount, would amount you to loose much more in the whole scenario.

what you want is basically not possible.

PLEASE REFER TO http://en.wikipedia.org/wiki/Perpetual_motion for more on these perpetual motion machines.. though very exciting, they are not feasible.