How Do Physics Students Handle Uncertainty in Problem Solving?

[snatchingthepi]

So I'm now a third year at a Canadian university in a theoretical physics programme. I have a simple question. How do you all deal with answering assignment questions without being given what the final answer is?

Let me clarify.

Say you have a question that asks you to compute the moment of inertia of some odd extended body given certain parameters (like I recently did). I set-up the situation, looked through my notes for the relevant equations, did some math, and got an answer that by all means is completely reasonable and had the correct units.

My problem is that until I hand-in the assignment and get it marked and returned, I have NO IDEA if my work is correct or not, and this bothers the hell out of me. I may very simply be spoiled. The first and second year "majors" courses at my institution were all taught by the same two/three professors who when giving assignment questions would put a little blurb at the bottom of the assignment page giving the final answer to each question. Not a solution, no work of any kind would be shown, just the final answer, like I_{CM} = 0.000956 \left[kgm^2\right]

What do you all do? I may just be a little of an anxious perfectionist, but I took great comfort in having the final answer as a resource.

 

[Choppy]

You just have to get used to it, I'm afraid.

It's great to have a final solution on hand so that you can check your work. But remember, the point of doing these exercises is to train you for situations where the final answer is not known. At the first or second year level, it shouldn't be too difficult to find the answer to a given problem somewhere. You may not find your exact problem and its solution, but these days it's pretty easy to find something similar and this can tell you whether you're on the right track. Once you go beyond that though, once the problems become more involved, it gets harder to find solutions. Hopefully though, you grow confident enough in your foundational skills that you can develop confidence in your response.

 

[snatchingthepi]

Extremely helpful response.

Other than the "like" button is there any sort of reputation or star or w/e system for praise/criticism of comments? I'm new here.

 

[jack476]

Well, you're theoretical physics, so maybe this would be a good time to learn how to construct mathematical proofs?

Also, another piece of advice for working large problems: Since I'm a bit neurotic about notebooks and have a problem with sloppy handwriting, I've found that numbering my steps and giving a brief statement of what I'm doing in that step can be extremely helpful when I get stuck.