Mastering Physics Problem Solving: Tips and Rules for Success

[FScheuer]

Generally, what are the steps in solving a physics problem? Some problems are straight forward, and you can just plug some numbers into an equation to get an answer, but with other problems, I sometimes don’t even know where to start. I generally just solve the problem by fiddling around with random equations until something works. Are there any steps or rules to makes things a bit easier. I think I heard that the number of equations should be the same as the number of unknowns for example.

 

[ZapperZ]

Here's what I gave my students on the very first day of class each semester:1. Read question carefully.
2. Identify the concepts or principles that are relevant. There may be more than one.
3. Draw a picture/pictures. Picture may need proper coordinates axes to define directions and positions.
4. Write down what are given or known, and what quantity/quantities that you need to find.
5. Write the most general form of the equation involved. This is your starting point.
6. Adapt that equation for the problem on hand.
7. Solve algebraically as far as possible. Resist inserting values till the end.
8. Look at final answer. Does it make sense? Are the units correct?

Zz.

 

[jbriggs444]

4. Write down what are given or known, and what quantity/quantities that you need to find.

For steps 5 and 6, I tend to think in terms of a tree search. A "meet in the middle strategy" can be employed:

What simplifying or clarifying assumptions can be made? Write them down.
What additional facts can be deduced from the givens of the problem? Could any of these be useful for the solution?
What additional facts would allow an answer to be calculated if they were known? Could any of these be deduced?

One is searching, of course, for a chain of equations that allow the solution to be derived from the givens.

 

[DS2C]

This video is basically a restatement of what's been said, but I've had success with this in any class.