Is creating your own "experiment" considered cheating during a physics exam? Consider a qualitative question on a physics exam such as, draw the path of an object's center of mass as it is dropped. I have included a graphic here:



Would it be considered cheating in practical terms if I were to make a mark in my pencil and drop it on my desk to observe its path? This is just one example of something that could be helpful on a mechanics exam.  

In general, would a professor consider the act of carrying out a small physical experiment during an exam as cheating as long as it is with reason and does not interfere with other students? By experiment, I mean something of the nature of what I mentioned earlier; I am talking about something that can be done with the instruments you are allowed to have during the exam. I do not mean using lab equipment.

To clarify, I something like this would be to gain a physical intuition of a solution. For the example listed above, simply dropping your pencil can give you an intuition as to the path its center of mass takes. This isn't intended as a substitute for work for a more complicated solution. 

I ask because I doubt and am currently unaware of any rule that prohibits this.
No, this is perfectly fine. In physics, it is common to see students making odd motions as they think through the problem or apply rules like the right hand rule. The usual caveats apply: you must not be distracting or obnoxious, must not broadcast data that other students could use to cheat, and must follow all announced regulations.

Yes, like with anything else, there are a million corner cases and caveats and unreasonable proctors that we could have fun trying to anticipate -- but I suggest we find more productive ways to spend our mental energies.