Why Can't I Solve Physics Problems Despite Being Good at Math?

[rudolf141]

poor physics problem solver ! help!

Hi everybody!

I m a physics undergraduate student in England and really suck at problem solving.I don t know ,probably I don t get the concepts well enough...my maths skills are quite good but sometimes I spend a half an hour on a problem the others need minutes. And I m clever,I have already a degree,or actually I might be in Physics
So I thought that if I don t have results till summer I rather quit or be kicked out.

I m looking for book recommendations ,which would take me gradually from easy problems towards harder ones.

I really need help,I try my best ,just please recommend me some books ,for someone who wants but can t do much at the moment


thanks a lot

rud141

 

[Delphi51]

Beyond your math skills, you need a feeling for what causes what.
For example, when you see F = ma do you just see a linear relationship between force and mass? F = ma should look ugly to you; the proper format is a = F/m which clearly says "a force on a mass causes it to accelerate." Once you understand the causal meaning of every formula you can begin to translate a problem into the appropriate formulas. One of my favourites is the acceleration of an electron in the electron gun of a television tube. It goes something like this:
A potential difference across the gun causes an electric field in it which causes a force on the electron which causes it to accelerate. That's the thinking. The solution is to think or write
V -> E -> F -> a
Then write the formula for each arrow or causes statement and do a bit of math to come up with a formula for acceleration as a function of V.
If the appropriate formulas don't come to mind instantly, spend some time writing each formula you've taken as a causes statement in words.

Practise greatly increases skill, too.

 

[rudolf141]

thank you for you advice Delphi 51.,it really makes sense even after the first reading.My problem may be somewhere in this area ,I don t translate clear enough the physical process mentally to understand it.

thanks so much ,I will practice

 

[Delphi51]

Most welcome, Rudolf.
I want to add an anecdote from my student days. It was an electronics lab in 2nd year and my friend and lab partner was a very knowledgeable theory guy with very little hands-on experience. When we were hooking up a transistor amplifier he was totally stalled on the concept that a wire had the same voltage on both ends. I had to explain it with Maxwell's Equations before he got it! Hard to believe . . . . but it really shows the importance of experience and work in the lab.

 

[rudolf141]

Very nice method Delphi51,good practice, I think that I ll improve my skills with your method.I m also going to order Schaum s set of problems to go over it.
I don t want to quit physics ,although sometimes is hard,I like it. regards,R