Rotate device keeping gravity pointing down

Physics
#1

Is it possible to have gravity always point down? An example would be to have a body on the screen, and rotate the device to try and keep it centered in the screen.

#2

if using accelerometer just set x,y gravity to xGravity*10 and yGravity*10

#3

if using accelerometer just set x,y gravity to xGravity*10 and yGravity*10