For an expanding sphere of air to be at sonic speed requires a certain pressure ( that can be calculated . ) However, it is a much higher pressure than can be achieved in a party balloon, so I suspect a popping balloon is not associated with sonic speed . t ) " 21 : 39, 18 October 2010 ( UTC)
32.
For an expanding sphere of air to be at sonic speed requires a certain pressure ( that can be calculated . ) However, it is a much higher pressure than can be achieved in a party balloon, so I suspect a popping balloon is not associated with sonic speed . t ) " 21 : 39, 18 October 2010 ( UTC)
33.
Terry Pratchett often deploys this tactic, and has argued that ( at least on the Discworld, where light is slowed to near-sonic speeds by the intense magical field ) dark must be " faster " than light, because it has to be able to see the light coming and get out of the way in time . talk ) 12 : 16, 14 August 2010 ( UTC)
34.
A de Laval nozzle will only choke at the throat if the pressure and mass flow through the nozzle is sufficient to reach sonic speeds, otherwise no supersonic flow is achieved, and it will act as a Venturi tube; this requires the entry pressure to the nozzle to be significantly above ambient at all times ( equivalently, the stagnation pressure of the jet must be above ambient ).
