# Understanding physics

Gale
I just don't get it. I can understand the ideas behind the formulas, and all that, but i can't ever use them right. Now, i don't have a specific question about anything really, i just need to figure out how to think about problems the right way so that i know what to do with them. I just sort of stare at them and write down all the formulas i can think of. Not a great way of doing things. I just don't even know where to begin.

## Answers and Replies

Staff Emeritus
Science Advisor
Gold Member
When you're doing homework, the first thing you want to do is write down all the relevant formulas on a single piece of paper. This serves as 1) a brain dump... lets you know what you've memorized, and what you still need to work on remembering 2) works as a great study tool for finals 3) saves you time constantly looking up formulas from all over the place.

Then, read the problem carefully to determine what information is given, and what information you're solving for. From there, pick the formulas that have all of the variables except for the one you're solving for.

Past that, practice is key. If you do enough of them, you'll begin to see that the problems are all very similar to each other. You'll begin to recognize that you did "that problem" before with different numbers or going backwards.

KLscilevothma
Originally posted by Gale17
I just don't get it. I can understand the ideas behind the formulas, and all that, but i can't ever use them right. Now, i don't have a specific question about anything really, i just need to figure out how to think about problems the right way so that i know what to do with them. I just sort of stare at them and write down all the formulas i can think of. Not a great way of doing things. I just don't even know where to begin.
Here are my suggestions:

1. There must be examples in your textbooks after each chapter. Read them and understand them thoroughly before attempting to do questions. As enigma has mentioned, the questions are quite similar to each other.

2. Practise makes perfect.

3. Find good reference books

4. Learn from mistakes

I remember 3 years ago, the time when I started to learn physics, I had a test on machanics after learning the relationship between displacement, velocity and acceleration. I started doing revision on the night before the test and felt really frustrated when I failed to answer the first few questions in my question book. I went back to read some examples first before attempting the questions again. Since the questions are quite similar, after reading the examples, I could tackle the questions well. I did more than 20 questions on this non-difficult topic.

Now my physics syllabus harder than that in 3 years ago. I remember once I did more than 100 questions on the topics rotational dynamics and simple harmonic motion fews day before test!

Work hard !

Science Advisor
It's vital that you understand what every equation MEANS. If you can apply meaning to an equation beyond a bunch of numbers and symbols, you will find it much easier to a) remember the equation and b) apply it correctly.

I suggest that you spend time (with a tutor if necessary) going through each equation and understanding:

What each term means and its signifigance.
Where the equation comes from. Not a detailed derivation, just enough understanding to know where each term comes from.
Any assumptions made in deriving the formula.
When the formula can be applied and when it cannot.

Once you have done this, practise questions from past exam papers or textbooks. Past exam papers are ideal as questions tend to get repeated from year to year, as well as giving a general guide as to the difficulty of the paper. Textbooks, however tend to have better worked solutions.

If you understand the equations and the material (not merely being able to recite them), then you ought to do well. Good luck.

Claude.