Flashcards in 8.4 Hydroelectric Power Deck (6):

1

## What happens is a volume of water delta V with a height h above a chosen horizontal level drops what happens to the gravitational potential energy?

### It is converted to kinetic energy as it flows through the pipe at the bottom.

2

## How is the mass of the water related to its potential energy?

###
Mass is m = delta V where p is the density of water so its potential energy is

mgh = pdeltaVgh. The rate P (power) at which this potential energy is converted is therefore

P = p (delta V/delta t) gh

3

## If the surface area of the dam is A then what is its volume and how will this affect the rate at which its volume changes?

###
V = Ah

delta V/delta t = A(delta h/delta t)

so P = pA(delta h/delta t) gh

The power depends on the height of the water and the rate at which the height changes.

4

## What are the advantages of hydroelectric energy?

###
Unlimited energy supply

No extraction costs

Clean

5

## What are the disadvantages of hydroelectric energy?

###
Very location dependent

Dams and reservoirs require serious changes to the environment

High initial costs

6