After blowing up a balloon, you release it without tying off the opening, and it flies out of your hand. If the diameter of the balloon is 6 in., the pressure inside it is $1 \mathrm{psig}$, and the opening is $1 / 2 \mathrm{in}$. in diameter, what is the balloon velocity? You may neglect friction in the escaping air and the weight of the balloon and assume that an instantaneous steady state (i.e., a "pseudo" steady state) applies.