title: how to change the speed of moving box2d object in cocos2d after touch on ccsprite
body: <p><img src="https://i.stack.imgur.com/p38be.png" alt="enter image description here">i am working on a ios game by using cocos2d .
  in my scene clouds are moving right to left direction with different vilocity.
  1)i just want when user tap on a cloud it moves more fast left to right.
  2)when clouds will go outside of view then it again appear from left side and start moving to left in normal speed.</p>