Naked Science Forum
Non Life Sciences => Technology => Topic started by: brainzlol on 04/01/2013 12:53:01
-
Does the moon have a pulling effect on a big object, like a building?
I know it attracts the sea to make tides.
What if a skyscraper was built on pistons (moving freely)? Would the moon pull and
release the building, thereby moving the pistons to create energy?
Thanks.
Mike from:
<please read the forum's A.U.P. before posting links to external pages. Thanks, Mod>
-
I am sure you could obtain some energy in this manner but I shudder to think what the cost per MW of the generator would be.
-
I could imagine a spring system under a large building allowing it to move with the solar and lunar tides. Japan, of course, has some extreme earthquake suspension systems built into many of their buildings already. But, about how much would it produce?
Ok, the diurnal change in gravity (http://en.wikipedia.org/wiki/Gravity_of_Earth#Other_factors) on Earth due to the sun and moon is about 2 µm/s2.
The (previous) World Trade Center Towers weighed somewhere on the order of 500,000,000 kg
So...
F = ma
m = 500,000,000 kg
a = 2 µm/s2 = 2 x 10-6 m/s2 = 0.000002 m/s2
So, F = ma = 500,000,000 kg * 0.000002 m/s2 = 1000 kgm/s2 = 1000 Newtons
1 newton = 0.2248 pounds
So, you end up with a difference of about 225 lbs, occurring twice a day.
Work, of course, = Force x Distance, with the distance being something pretty small.
Anyway, you would be much better off attaching a dynamo to a single bench press machine in the gym in the building.
Or, you could think of it as the force exerted by 1 or 2 people entering or leaving the building (which otherwise has an occupancy of thousands).