Conservation of energy water turbine problem

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Homework Help Overview

The discussion revolves around a conservation of energy problem related to a water turbine, where the original poster attempts to calculate kinetic energy using gravitational potential energy and questions the conversion of energy forms in the system.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the application of the conservation of energy principle, questioning the necessity of using specific equations and the implications of energy conversion in the context of the turbine's operation.

Discussion Status

Some participants have provided feedback on the calculations and suggested maintaining unit consistency. There is an ongoing exploration of how to determine time in relation to power output, with one participant asserting that time is known to be one second.

Contextual Notes

There are indications of missing information regarding the specific setup of the problem, as well as assumptions about the efficiency of energy conversion in the turbine system.

TheRedDevil18
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Homework Statement



a3jsbs.jpg


Homework Equations



mgh=1/2mv^2

The Attempt at a Solution



7.1) 200*1000=200000kg

7.2) Must I use mgh? They asked for kinetic energy but energy is conserved so:
200000*9.8*150
= 2.9*10^8 J

7.3) Ep=Ek
2.9*10^8=1/2*200000*v^2
v=53.8 m.s

7.4) 85% of 2.9*10^8
= 2.5*10^8 J

7.5) It gets converted into heat and sound when it hits the turbine.

All good?
 
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The electrical power output is energy per time, it has Watts as unit.
The numbers look fine, but you should keep their units in the calculations. In addition, it would be easier to understand your solutions if you start with the formulas first, and plug in numbers afterwards.
 
p=w/t, how to find time?, must I use equations of motion?
 
TheRedDevil18 said:
p=w/t, how to find time?, must I use equations of motion?
Nope. You already know that the time is 1sec.
 

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