Gravity

#1 You can change gravity either using a method or directly altering its field in the Scene:

%scene = new Scene();

// Update gravity using the method.
%scene.setGravity( 0, -9.8 );

// Update gravity using the field.
%scene.Gravity = "0 -9.8";

When you set the gravity you set it through the x/y axis. Each axis is specified in metres/sec therefore setting -9.8m/s (Y Axis) gives an approximate earth gravity. Gravity affects all "dynamic" bodies in the world.

#2 Moreover, you can set how scene gravity affects your objects using:

%obj.GravityScale = 1;

// or
%obj.setGravityScale(1);

// if you want your object to stop being affected by gravity
%obj.GravityScale = 0;

When you set the gravity scale of an object its gravity equals scale*scene gravity.