How to improve problem solving skills

[Galactium]

Hello, I'm new here so forgive me for my ignorance. I am currently a freshman majoring in Physics. I am having trouble trying to understand the concepts in my physics class. In high school I took precalculus and regular physics. My physics teacher was good, but had some trouble expressing his steps and ideas which confused me a bit. He would literally tell us to plug in the numbers. Whereas my current physics class we have to use critical thinking skills to full understand the material. I have never been trained to think outside of the box so my problem solving skills are extremely lousy. Somethings that I have tried doing was to read my physics book go online for tutorials and do some basic problems then build my way up to the harder ones. I always go to both my professor's and TA office hours to get more out of the Learning experience. However, most of these things aren't helping. I am starting to think that physics may not be suitable for me due to my skills. I also downloaded a few apps on my phone to help me, but most of them don't offer that much information. Any suggestions/recommendation I should do in order to improve my skills?
Thanks.

 

[jbriggs444]

Some general advice, worth what you paid for it...

The way to get good at solving problems is to solve problems.

One approach is to start by writing down what you know. And think about what other things you can determine based on what you know. Then write down what you are trying to find out. And think of other bits of information that would help you find that result if you knew them. This might be called a "meet in the middle" strategy.

Another handy skill is the ability to identify and discard extraneous information. The more irrelevant tidbits are cluttering your mind when you are working a problem, the harder it is to keep track of the pieces that matter.

Another helpful tool to cracking problems is to look for symmetries and conservation laws. If you know that a quantity is conserved then you can ignore huge swaths of irrelevant information and jump straight from an initial condition where the quantity has a known value to a final condition where that quantity must still have that same value. For example, potential energy at the top of a hill and kinetic energy at the bottom if the problem indicates that friction is absent. [I am having a hard time thinking of a good example where an argument from symmetry works]

For some people, writing down names for all the variables and writing down equations to express all the givens of the problem works well. They can then proceed to solve the resulting system of equations with algebra to deduce the final result. If you are working problems where your physical intuition fails (and all of us get there, eventually), this method may end up being the only way to proceed.

Edit to add: Get in the habit of doing sanity checks on your work. Do your answers make sense? Do they have the right units? Are they unreasonably large or small? If you plug an answer back into the corresponding question, does it meet the requirements? If you calculate the result one way, does it match with the result calculated a different way?

If a problem is totally kicking your butt, turn it around. Try to prove that the result you are after cannot be determined by the inputs that are given. Try to find some other way that you might change the output without altering the fixed inputs.

[Most of these things work just as well for doing mathematical proofs as for working physics story problems]

When thinking about the difference that minor effects have, a useful approach can be to consider what would happen if those effects were extreme e.g. If I increased the force by a factor of 10000, what would happen? This can be helpful when deciding whether a formula should be directly proportional, inversely proportional, proportional to the square root, etc.

Oh, you did draw a free body diagram, right?