Steve:
The whip’s pop is a result of the tip of the whip (the “popper”) moving beyond the speed of sound and creating a vacuum in space. The air rushing back into the vacuum makes the pop sound. A whip generates its speed through the “conservation of energy”. The body of the whip is built to be a continually shrinking diameter from the thick handle down to the tip of the popper which is only a few strands of fiber. A little energy imparted at the handle accelerates along the diminishing diameter until the popper is moving over 700 miles/hour. You scientists can post the exact speed of sound (someone’s .sig says that “the speed of time is one second per second” 🙂
The speed of sound is 343 Meters per second or about 154 miles per hour in air, sound in other mediums has a different rate of travel. Air temperature and air density (mostly from humidity) effect this speed but it is good enough for general discussion purposes