"random force" is surely odd phrasing, but that's what they used in their experiment. If the coins aren't affected by air (which, oddly, they didn't specify, but I suggested they shouldn't be), and haven't hit anything, then we can imagine most "random force" distributions to choose uniformly a random orientation (because the random distribution goes high, and enough time has passed to do so, even if the starting orientations are all the same). Most importantly, if we assume we can answer the question, then initial orientation can't matter because it wasn't specified.