Gravity in unity android

Hello, i have made a plumb-bob using hinge joint and fixed joint and i want it to effect with gravity and it goes to right when i tilt my phone to right and left when i tilt my phone to left. but i do not know how can i achieve that?

can anybody please give me some hint how can i achieve that? it will be really appreciative.

thanks

http://unity3d.com/support/documentation/ScriptReference/Input-acceleration.html