Yet more surprises marking exams … a question on friction … a number of answers began with

F = μ N

followed on the next line with

N = 6.02 x 1023 …

What?! This one threw me for a bit. After some searching I realised that Avogadro’s number was listed with other constants on the front of the exam. But, N was never used for the normal force in the notes or the textbook …. more searching found it in the formula sheet at the back of the exam.
So the question was approached as a pattern recognition exercise with absolutely no context, the access key was probably the symbol μ tiying it to friction…
Why is the Turing test supposed to be hard?