Ok it's about fluids. You have a tube 100% full of water, no air at all. Corked both ends. Hit the one cork with a hammer, the amount of force that it hit with is = to the force that hit the other cork. and knocks it out. Now I was once doing collissions and I was trying to find a situation which has 100% efficiency. I eventually failed to figure out one. As no vacuum could ever be perfect in practice. So I asked my teacher if there could possibly be a 100% efficient thing. He said there is nothing at all which is 100%. Then did the speech about car engine is only 40% efficient. and alot of other things. Now I find that this Cork water situation isn't 100% efficient as per other situations. My teacher said something along the lines that it is = to the other force. Seemingly 100% efficient cause of the "=to" Which is right? I can understand that its very very close and the air resistance would make the total amount not 100%, but transmission from cork to cork cant be 100% is it?