Is there a way to unlock a password protected iPad?
I'm not sure a general answer can be given with the lack of details in this specific case, but like any data recovery situation, it pays to stop and get some professional help to at least understand your options.


How valuable is the data? Give an order of magnitude guess. $10, $100, $1000, $10,000, or more? The solutions for each involve different timescales and tools.
STOP trying to guess the passcode - it could have a 10 guess and the iPad erases itself trigger set. The trigger could even be less than 10 incorrect guesses. Your next attempt to unlock it could be your last chance to save the contents.
What else is available? In almost all cases, a computer exists that will unlock each iOS device - so rather than trying to guess the passcode - see if you can locate that computer instead.


Here are support articles that should help anyone in this situation:


iOS: Understanding passcodes  - http://support.apple.com/kb/HT4113
iOS: Forgotten passcode or device disabled after entering wrong passcode  - http://support.apple.com/kb/HT1212
iCloud: Find My iPhone overview - http://support.apple.com/kb/PH2696


Once you realize that time is on your side and that the system is designed to not be compromised by someone that finds the device, your chance of success will increase with the added care you bring to the task. That design notwithstanding, there are often circumstances when a passcode gets forgotten or not handed to the device's current owner and you have a few avenues to get the passcode reset or bypassed without erasing the device's contents whether you try to crack the PIN with a tool or work around the security by locating the computer that can unlock the device for you.