Whining Sound, Please Help!!!

Hi all,
great site! I am looking to buy a 2002 Liberty but, when I test drove it, it had a noticable whining sound when you take off from a stop and increases with RPMs, it sounds like it's comming from the engine. It only has 36,000 miles on it. Does anyone have this problem? I think it could be the belt... Please Help.

Thanks,

Brad...

could be the ac compressor clutch. i had to replace compressor cause clutch bearing went bad. mad a lot of noise