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Re: [Phys-L] mach 1.4 table tennis ball



A progression was shown: a short (6 ft) acrylic tube, pumped out then punctured on the back closure. A long (80 ft) tube similarly prepared whose performance was disappointing: the ball stopped before the muzzle with the leakage gas slowing
the ball to a halt, finally, a deLaval nozzle with a pressurized gas cylinder behind it.

I would have enjoyed seeing just the effect of a deLaval nozzle in the atmospheric air inlet. Such a nozzle can certainly get a sonic air jet into a vacuum chamber using just atmospheric air pressure.

Brian Whatcott Altus OK

On 3/2/2014 1:49 PM, John Denker wrote:
Hi --

Heads up: You might get asked about the following:

The Mythbusters episode that aired yesterday Sat 1 March 2014
included a ping pong ball cannon with vacuum in the barrel in
front of the ball and 300 psi behind the ball. The muzzle
velocity was 1100 miles per hour. That's enough to blast a
round hole in an ordinary wooden table tennis bat.
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