Simple Grenade Physics/ Movement type not working if object created in run time

I am trying to create a simple grenade in a top down shooter game.I have tried to make my own physics but It did not work.Now I am using the built in pin ball movement, and It works but only when the object is already placed in on the editor, but I want it so you can launch the grenade in a direction and it will be able to bounce of walls but have a speed decrease.Any ideas on how to fix this, if not maybe you can tell me how to create my own physics, thanks.

I would think that you'd use the bouncing ball movement for a top down shooter.

I figured it out.i still used pinball movement but instead of launching the object i just created it at my character and made it face my mouse so it launches towards it.