In unity a beach ball sized object will fall straight through a mesh collider after free falling from 10 meters ( 32 feet ).
Drag = 0.001 as recommended here Unity - Manual: Rigidbody component reference for a solid metal object.
Mass = 6
-The mesh collider is a default unity plane.
-The beach ball is a unity sphere with rigidbody and sphere collider. Scale =0.5
-I stacked 10 default cubes on top of each other to ensure it was dropping to scale at 10 meters.
Is this expected behavior?
You may need to increase the physics rate. I think that is in the Time settings area. Also you can play with the intersection penalty in Physics settings.
This is typical behavior with most physics engines. There is no width to the physics object you’re trying to collide with, so in one physics time step the entire rigidbody is on one side of the a plane and on the next physics time step it is on the other side of the plane. The physics engine does not detect the collision. To fight this, either use a box collider with a larger width or use a convex mesh for the mesh collider.