bout0046

Oh ok, that makes sense. I was trying to do it in English units; I was being lazy . I think I understand it now. Thanks everyone for your help.

So by using PV=1/2mv^2 where v is velocity, and V is volume of air chamber, P is pressure of air chamber, and m is mass, I can get the initial velocity of the object as it's leaving the barrel? And from this I can just use equations of motion? So solving for v, I get v= Sqrt(2PV/m), but this leaves units in a length I think. But this doesn't make sense to me.

For the longest time I have been trying to figure out how far a projectile will go after being launched from an air cannon. I'm trying to figure out how big of an air chamber I will need to build to shoot a certain object so far. I was looking around and found someone saying that PV=1/2mv^2 gives a good estimate, but I wasn't too sure and confused about when solving for v, you're only left with a length(I think). So I am wondering if someone could help me figure out either what the velocity of an object would be as it's leaving the barrel, or how far it could go. The pressure of the air chamber, volume of air chamber, mass of object, area of object, length of barrel, will all be known. I'm not looking for anything super accurate, so anything like wind, friction, etc. can be ignored. I have been trying to do this for a while now and can't seem to come up with anything. Years of physics and I can't think about what to do, haha. I don't know if maybe I'm over thinking or it's harder than it looks. Any help will be greatly appreciated. Thanks