A student designs a gas powered launcher that consists of a pressure tank, a valve and a barrel. When the valve is turned the gas, in this case air, expands propelling whatever is in the barrel. The pressure tank and barrel have the same dimensions while the valve connecting the two has a diameter of 25 mm. Assume the valve instantly opens. How much force in newtons is generated when the valve is opened at the exit end of the valve (point X)? Please help me, I'm totally lost :( I actually made this question as I have built this launcher and am wondering what its power theoretically is. I was never taught how to do this.