The discussion revolves around the relationship between friction and the number of surfaces in contact with an object, particularly focusing on scenarios where the angles between surfaces vary. Participants are exploring the implications of these angles on the normal forces and frictional forces involved.
The discussion is ongoing, with participants questioning each other's interpretations and assumptions about the setup. Some have suggested that the normal forces must be analyzed in relation to their angles, indicating a productive exploration of the geometry involved.
There is a noted complexity in visualizing the problem, particularly regarding the angles of the surfaces and their contributions to the normal force. Some diagrams referenced do not align with the original setup, leading to further questions about the configuration of the surfaces.
The safe way is to consider each surface separately, making sure to use only the normal force that applies on that surface in each case.kftheuidfnaks said:
If the surfaces are of equal material, you essentially end up with twice the frictional force?haruspex said:
No, that's not what I wrote. Consider e.g. when the angle is opened to 180 degrees. It is now one surface, so not doubled.kftheuidfnaks said:
Am I thinking of your proposal wrong if I split the block in two, one left and one right of the center when its opened to 180 degrees?haruspex said:
Unfortunately it is more complicated than that. The normal forces, by definition, act at right angles to the surfaces. So to find the contribution of each to supporting the weight you need to find the angles the surfaces make to the horizontal . This is a tricky bit of 3D geometry.kftheuidfnaks said:
I'm not sure what the set-up is in the above diagrams. None of them match the diagram in post #1. In particular, none seem to involve two surfaces. Is that intentional?kftheuidfnaks said: