Dwight,
More food for thought:
Picture a car accellerating at full throttle at 7,000 rpm. Lets say hypotheticaly that the exhaust is entering the muffler at 600 mph. By your way of thinking the exhaust would leave the muffler at 200?, 300?, 400mph??? I think not. That would mean the muffler was holding all that exhaust and getting bigger and bigger. If the exhaust goes in at 600mph. it comes out at 600mph.
EXHAUST has VOLUME and MASS. To store it the muffler would have to grow and get bigger as you drive. Sound waves have NO VOLUME and NO MASS. They are what get absorbed and/or cancelled out within the muffler.
I think you are trying to compare this with a gun. It is not the same thing. A gun is an instantanious discharge. Exhaust is a continual flow.
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