what you waiting for?
http://allabouthow.blogspot.com/2009/01/pass-your-ippt-test-for-pull-up-in-60.html
this seems suspiciously like an advertising ploy..
study physics to understand all the mechanics of IPPT la
http://ezinearticles.com/?Physics-in-a-Nutshell-For-O-and-A-Levels&id=1759215
or simply visit Homework Forum to ask.