easy, assign this action

:
Code:
var earth_gravity[3] = 0,0, -886;
action physics_ent
{
phent_settype(my, PH_RIGID, PH_poly);
ph_setgravity ( earth_gravity );
phent_setmass(my, 10, PH_sphere);
phent_setfriction(my,10);
phent_setelasticity(my, 40, 1);
phent_setdamping ( my, 10, 25 );
}
regards,
EDIT: oops forgot the earth gravity variable :P