What exactly are you trying to achieve?
Angular velocity is the speed of rotation. And density is basically mass of the object. Adding them together makes little sense.
I'm guessing you need normal (linear) velocity. You can use VelocityX if your ball is moving horizontally, or this expression to get its overall velocity:
distance(0, 0, Ball.Physics.VelocityX, VelocityY)
Also, you should probably multiply velocity and density together, not add them.
Add a text object to your layout and print the result of this formula to see what numbers it's generating.