# 2nd and 3rd year physics homework length/difficulty bewilderment

Hi,

I have a general question about physics homework after the first year. It is a mix of bewilderment and apprehension. I'm doing very well in my first semester of calc-based physics, and I knock off the problem sets in a few hours. But I hear that the first year is relatively mild, and things get crazy in years two and three. My professor said, for example, that in upper level mechanics he gives 3 problems a week and it should take me around 18 hours to do each set of 3 per week. Now if that is the general case I have a few questions:

What is meant by 18 hours (I understand the exact number 18 isn't definite, but loosely speaking from what I research a 3 course physics load takes around 40-50 hours of work/week)? Given that the solutions are generally a few lines, or a page at max - it must be the time spent thinking about how to solve the problem, yes? Does this mean 18 hours of thinking about the solution, including all the time you take breaks or are just spacing out because you're clueless? Or is it 18 hours of nonstop mental labor to the solution?

Is this time length a result of having to become familiar with the physics/math you are being taught while you solve the problems, so some of those 18 hours are studying, and not really working on the homework? Or even when you are familiar with the mathematics and the physics, solving the problem still takes 18 hours?

Forgive me if these concerns sound naive or cowardly, I just cannot currently fathom how 3 problems can take 18 hours. Sure, I'd be lying if I said there was no lazy streak in me, but at the same time I really do like physics and I want to take the upper level stuff (i.e. major in it), I just cannot currently fathom why a 3 problem set would take 18 hours of time?

Does it also vary tremendously from student to student, or in the upper level stuff is everyone struggling to stay afloat?

The more detailed the better, but any clarity would be greatly appreciated. Thanks in advance to all who can help

p.s. - if all else fails, there is always biology for me :)

you'll be fine, cross that bridge when you get to it.

6 hours a problem is high but not impossible. Assume this includes short breaks, getting a drink etc. I remember working 10 hours a day over the summer to learn real analysis and averaging 3 problems per day. Still I'd guess a 3-problem p-set will take 9-12 hours which is actually about the ideal amount of weekly homework. This is just a guess though. If you doing well now relative to your classmates you will probably do well later relative to your classmates if you put in as much work as them.

40-50 (not counting class) hours a week is what most people need to do first class work in physics/math. More then once a single problem (I eventually got) took about 20 hours, usually i get help before that point.

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Some problems in E&M take me forever. That's just how it is. You will have enough time if you pay attention in class. Also normally when they say "3 problems" they really mean like 3 5 part problems.

lisab
Staff Emeritus
Gold Member
Given that the solutions are generally a few lines, or a page at max -

Well...that's not a given, actually. The solutions can take many pages. Sure, you spend some time thinking. But a *lot* of time is spent trying different approaches, too. So there are a lot of failures before you get there.

Forgive me if these concerns sound naive or cowardly, I just cannot currently fathom how 3 problems can take 18 hours. Sure, I'd be lying if I said there was no lazy streak in me, but at the same time I really do like physics and I want to take the upper level stuff (i.e. major in it), I just cannot currently fathom why a 3 problem set would take 18 hours of time?

No, you don't sound cowardly. A bit naive maybe , but that's totally OK and to be expected since you're just in your first year classes. Things change *radically* in the third year, but if you do well in your first year classes that's a good predictor that you'll do well in the upper level classes. Your professor's assessment seems about right to me. At least that was what I experienced - especially in E&M.

If you like it, and you have determination, you'll be fine.

Your professor isn't kidding, you will probably spend that much time on upper level physics homework. I think the last problem set I did in classical mechanics 2 took me probably 20 hours total for 7 multi-step problems. When I first entered the program I heard someone in E&M say "don't be surprised if it takes you 17 hours to do 3 problems." The longest I have ever spent on a problem is 15 hours before I just accepted there was no way I could figure it out without help. This isn't always the case though, and it definitely depends on the professor and individual.