Not quite what was looked for, but my answer / analysis of Not Far (one of the earliest problems in Mechanics):
This problem asks you to determine what distance has been traveled, based on pseudo-integrating a graph of speed vs. time. ! Notably, the graph appears to have three square units of area above the y-axis, and three square units of area below the y-axis. If these are each in fact identical squares, they would cancel out, and there would have been no net-distance traveled. !
! The problem then asks “Look at this speed graph and tell how far away from the starting point this thing ended up.”, giving the options: ! a) It is impossible to tell because the graph has no numerical scale on it. ! b) It ended up at the starting point. ! c) It did not end up at the starting point but where it ended can’t be told. !
! I pretty firmly believed (and still believe) that the answer here is a: Not only does the graph not not have a numerical scale on either axis, but there are no other indications either that these squares are equally sized. ! Still, I anticipated that the workbook might be trying to teach a different lesson: Not something like ‘without units, be careful of interpreting graphs’, but something more like ‘positive and negative distances can cancel out’. ! Accordingly, I didn’t put ~100% on a; instead I did a 90-8-2 split across these, getting it ‘wrong’ when the answer was deemed to be b. !
! I notice that I’m pretty frustrated to have gotten this one ‘incorrect’, and that I was kind of muddling between two different levels of analysis: 1) what is my confidence in the correct answer to this problem, and 2) what is my confidence that the answer I deem correct is the same one that the author deems correct. I really did not want to have to be considering 2 that deeply when giving my probabilities, but I guess the cost of that will be getting a lower predictive score than otherwise. ! I also notice that I’m really searching out for someone/something to validate my experience of having been ‘robbed’ here. But from what I can tell, the Internet does not have much other discussion of this specific problem. I feel my trust kind of broken by this particular exercise, and I’m bummed to have encountered it so early on, but also feel like I’m kind of shouting out into the void by sharing this. (I am finding the exercises on the whole to be useful though and do not at all regret having gone through the ones so far.)
Whoops, that was a typo—corrected the probability now in the thread, & thanks, that’s helpful