Hydroelectricity Flashcards
potential energy
stored energy, pe=mgh
kinetic energy
energy of movement, ke=1/2xmassxvelocity(2)
tides
sun/moon gravitational pull differences, sun is stronger moon is closer, 2 high and low tides a day, 12.5 hrs apart, 50 mins later each day
force
mass1 - mass2 /distance
tidal bulge
bigger pull on one side by moon
inverse law
as distance increases force decreases, 1/d(2)
why does moon have bigger pull than sun
as its closer to earth, 1/dist(2)
high tide
nearest and furthest from moon
low tide
moon is right angle to earth
spring tides
moon and sun allign
neap tides
moon and sun at 90 degrees
hydroelectricity
water builds up at top as PE and is released and turned to KE and energy is extracted through turbine
tidal power
uses tidal movements to extract energy, ocean not enough energy, estuaries have high amplitude
tidal flow systems
propellers extract KE between 2 islands
tidal barrage systems
holds high tide at barrage/dam and extracts energy as water flows out barrage
power of tidal barrage
1/2 x water density x area x gravity x height (2)
height
difference between height of high and low tide
power available in barrage
1/2 x water density x gravity x area x height(2)/2 x T
T
12.5 x 3600
Ebb tide system
2 bursts a day, water fills at high tide and flows out as outside water drops and generates electricity
efficiency of tidal turbines
80%
amplitude
wave height
frequency
number of waves per second (hertz)
velocity
speed
