Quote:
Originally Posted by Nesti
I've seen something similar in hydraulics, where there are 3 pistons with different surface areas, but connected to a common manifold which slowly increases the pressure until a single piston moves, however;
1. The 1sq inch piston has 10lbs on top of it
2. The 10sq inch piston has 100lbs on top of it
3. The 100sq inch piston has 1000lbs on top of it
If you dial up the pressure, which piston overcomes it's supported weight first. Common sense would say they all act at the same time...not so!
Conservation of energy somehow makes the 1sq inch piston move first.
The locking of smaller mass/energy to larger mass/energy isn't surprising.
I actually miss sequenced hydraulics...hydraulics in general is fascinating.
|
Hmmm
So, each piston sits in it's own cylinder and everything is connected with manifold to the same pump... and they are not connected otherwise (like on a same crank-shaft ?
The relative load on each piston is 1, 10, 100x.
Intuitively, one would think that the largest piston would start move because the force on it's head is the largest..
If we assume there is not friction between pistons and cylinders, all the pistons should start to move simultaneously...
If we take into account the friction, then we have an area between cylinders and pistons which is causing the friction, and the relative sizes of that area is proportional to the product of lengths of the piston (assumed the same for all of them) and circumference of said piston.. which will be proportional to the SQRT of piston head area.
So I think the biggest piston will start to move first, because the relative friction of the widest piston is lowest.
And, yes, the Moon rotates, one rot per ~27 days.
Where that axis is.. it is actually passing through the gravity center of Earth-Moon system.. I think Andrew is spot on here :-)