Fake hard aggrevation, and an appeal for advice.

[seanm1]

"Fake hard" aggrevation, and an appeal for advice.

I love math. And logic. And modeling things.

Outside of class, I even love physics.

Inside of class, I feel like someone playing Street Fighter for the first time against someone who has owned the game for a year.

Every time I get a question which is basically "rearrange an equation, plug in knowns, and turn it into a system of unknowns or just flat out solve it", my heart sinks in my chest, because I know for a fact I'm going to get the wrong answer, even with a calculator.

A big part of the problem is that a lot of physics questions throw a lot of concept testing into the wording. That's a very nice and polite way of saying physics test questions are typically trick questions.

Physics is basically a five step process for me:

-Analyze the problem, and find the relevant laws
-Work out the math as best I can
-Write down an incorrect answer
-Find out that the angle of refraction I was given wasn't normal to the plane, or that the collision wasn't inelastic, or that the space between the two capacitors was actually filled with something... you get the idea
-Buck up and restrain myself from crying and/or beating my head against my desk.

I'm not the type to throw his controller at the TV and scream when playing a video game. But if there were an equivalent with regard to physics, I'd be doing it day in and day out.

Another big part of it is that this is the way a physicist seems to think:
-Look at the problem
-Chunk it up into several smaller problems
-Use the similarities and differences between these smaller problems to eliminate as much junk as possible
-Solve one of the smaller problems

As opposed to the way I think,
-Turn the problem into a function
-Solve the function

The physicist's approach is just plain better than mine when it comes to situations where you can't trust the incoming data to begin with, and you only get one shot at getting an answer right. You know, like in a physics class. In my defense, I think my approach is a lot faster in "infinite retry" situations, like setting up a program and seeing if it compiles.

So I'd like to learn how to think like a physicist. I'll give another quick example to solidify my complaint and my request here:

Let's say you wanted to find a field. You are given an integral and a density function.

A physicist (and me now that I've gotten help with one of these kinds of problems) holds the density function constant, pulls it out of the integral, and looks up a basic solved shape.

I'm embarrassed to say that I get a good way into trying to solve the integral, making no assumptions about the shape being basic despite the evidence screaming at me.

I really used to think I was good at tests before I took my university physics class. Now, I've learned that any time someone wants to pull the wool over my eyes and trick me into thinking something's negative when it should be positive by the right hand rule, they are going to succeed.

I guess the best way I can sum up what I'm wondering is, how do I train my "street smarts"? I'm saying this as someone that's acing Calc and worried he's going to have to retake physics because of exactly this problem.

 

[twofish-quant]

Every time I get a question which is basically "rearrange an equation, plug in knowns, and turn it into a system of unknowns or just flat out solve it", my heart sinks in my chest, because I know for a fact I'm going to get the wrong answer, even with a calculator.

Just get good enough so that you get decent grades and don't worry too much about this. Running through an algorithm is a useful skill, but it has nothing to do with real physics. The good news is that you haven't be exposed to any real physics or real science, and so what you should do is to just work on getting your grades good enough so that you can get exposed to the real stuff in college.

So I'd like to learn how to think like a physicist. I'll give another quick example to solidify my complaint and my request here:

Let's say you wanted to find a field. You are given an integral and a density function.

A physicist (and me now that I've gotten help with one of these kinds of problems) holds the density function constant, pulls it out of the integral, and looks up a basic solved shape.

That's actually not thinking like a physicist. The way a physicist would think would be "are integrals or density functions the best way of modelling this situation. If it is then I write a computer program or plug the numbers into a program someone has already written and see if I get answers that seem to model what's going on."

If you want to do real physics, do some science fair project or try to get a summer job at a university. Also something that would help is if you get some computer programming experience.

I guess the best way I can sum up what I'm wondering is, how do I train my "street smarts"? I'm saying this as someone that's acing Calc and worried he's going to have to retake physics because of exactly this problem.

For passing tests, get as many old tests and as many solved problems as you can. There are only so many ways of writing a trick problem, and if you look at hundreds of problems, you'd likely seen them all.

Also, you'll need to learn how to pass tests to get where you want to go. Just remember that passing tests has very little to do with doing physics.