i play with box2d physic engine. I created world with 9.8 gravityy and true for sleep. I close the phone screen with chain shape. Lastly i create a ball with 100px radius. It's perfectly works no problem but i play with numbers about Fixtures. We have 3 options density, friction, restitution. I understand friction and restitution but i don't understand density. i change it to 1 and after that to 1000 but i can't see any changes in world. What does do, what it is
please explain, help ?