whip lash

[iheartruby]

why is whip lash called whip lash?

[heathfield]

It comes from what happens when someone cracks an Indiana Jones type whip, and lash is the sound the whip makes.
As to what happens, you move the handle of the whip and produce a curve in it. The curve travels along the whip, becoming smaller as it does so. As the curve gets smaller, it gets faster. When it reaches the end, it can be so small and so fast, that it is travelling faster than sound, and that sound you hear, the 'crack' ,is the end of the whip breaking the sound barrier!
If you're in a car that has a bump, your body acts like the whip. A jolt travels up the spine, and gets smaller and faster till it reaches the neck. If the jolt is severe enough a broken neck could result.