Tear
If you scrape a sharp stone against your skin, it will tear. The sharp stone tears your skin. It hurts!
Imagine this sharp stone. Feel its weight in your hand. Now drag the sharp stone against your skin. Feel your skin as it begins to tear. The pain is agonizing.
は
やぶ
None
The moment your skin tears you can't help but yelp "Ha (は)!" It sounds like a laugh, but it's more like a pained bark.
You make this noise when you tear other things with the sharp stone too, but now it's more of a HA! TAKE THAT! Feel the same pain I feel!