Suppose i have 4 empty syringes. And by empty i mean they were having the air sucked out of them, and they "contain vacuum". Assume the head of the syringe is blocked so vacuum can be formed.
I want to understand how to choose between this 4 different syringes.
My goal is to have the piston reach the highest speed possible. I don't know how to calculate what is better.. should i increase the diameter? - should i keep the diameter the same but make the syringe longer.. what is better?
When i release the piston - the atmospheric pressure will make the piston move pretty fast - and blow up the head of the syringe.
This is not a real world example. Just something for me to learn. I don't know what the piston friction with the walls is - but is the same for all 4 syringes so does not matter when comparing them.
Also i don't know the mass of the piston either.. i mean we can use a gut number like 0.25 kg. And the bigger piston is 1kg.
Also i'm interested in forming an intuition of what to expect given changes to the design of this syringes rather then exact numbers. What happens if i increase the diameter 3 times.. is it better or worse .. that kind of thing.
Does it matter how long the syringe is? Can it happen that if i make it too long then the piston is actually slowed down? Is this piston constantly accelerating while is in the syringe and there is still vacuum in front of it .. or not actually? Can air to air turbulence slow things down? Where is the highest acceleration at? Maybe in the middle of the syringe ?
I say this because if we go down to 1 mm tube, then capillarity is so high that you need to push on it like crazy to make things move. I'm thinking about what force is needed to squeeze that fluid in a medical equipment (needle + tube). So when it comes to tubes like this, maybe having a higher diameter is better?! Maybe this applies to air also?
I can put the numbers in a calculator and get the result, but i'm interested more on how to think about this, not just the formula. How do you break it down in your mind - and not be wrong?
But i do want to lean how calculate the exact numbers as well. Thanks :)