I bought a new macbook pro 2.9 ghz 8 ram 512 gb flash , and the battery is dying in less than 4 hours , without using it much, e.g. only safari,it's not supposed to last 10 hours? please help

First, please look at this Apple article on shortened runtimes:

Apps can affect Mac performance, battery runtime, temperature, and fan activity - Apple Support

If you have installed anti-virus or so-called "optimizing/cleaing/tune-up" untilites, they are prime suspects.

If the test in the article does not show any suspects, and you do not have any useless utilities running, then make an appointment with an Apple retail store or authorized service provider--your computer is still under warranty if you just bought it.