v = sqrt ((deltaP * pi * r^2 * l)/m)

where deltaP = 5 atm, r = 9 mm, l = 25 mm, m = 7.5 g. By converting to the SI units and inserting this into the formula, he gets an initial velocity of v = 20 m/s or 70 km/h.

]]>I find a velocity quite superior to the one you give here : 5 atm (relative pressure) on a diameter of 25 mm (area ~ 5 cmÂ²) gives a force of 250 N.

Assuming a weight of 10g, the resulting acceleration is 25000 m/sÂ².

After 0.002s the cork velocity is 50m/s, and it is only 5cm away from the bottle (so we can guess the pressure is still acting on it, although with rapidly decreasing intensity) … ]]>