Mechanics

calculus-based physics for scientists and engineers

Problem Solving Strategies

General Problem Solving Strategy: Introduction

One huge misconception students have is the idea that if you know the subject you should be able to know how to solve problems on that subject. That seems to make sense. They conclude that if they don't know how to solve a problem, it means they don't know the material well enough, they aren't smart enough, their instructor is incompetent, or some combination. However, this may not be the case. In physics, as in real life, problems can get so difficult that, even if you know the subject well, you don't immediately know what to do. In these cases, you need a strategy to get you started and a method to accumulate the information necessary to solve the problem. I describe how to do that here, starting with an introduction and some tips.

General Problem Solving Strategy: Visualize

The first step to successfully solve problems is to visualize everything going on. Visualize what is happening and what you think is going to happen. Do not rely on the description of the problem or any figures provided.

General Problem Solving Strategy: Brainstorm

This is where you will spend the most time. You aren't trying to solve the problem, but trying different ideas to learn more about what is going on. What approximations can you make? What physics applies? What does that mean? How can you use the physics that applies to relate what you know to what you don't know? Take a direction even if you don't know where it will end up. That is why this is brainstorming. Don't think about solving as much as understanding the problem. See what you can find.

General Problem Solving Strategy: Solve

Once you have enough information to solve, go for it. One hint: if you have the same number of linearly-independent equations as unknowns, you should be able to find the unknowns. (Roughly speaking, linearly-independent means the equations not derived from the same source.)

General Problem Solving Strategy: Check

You may not care about being right or wrong now, but when you have a career in science or engineering, being right or wrong can mean the difference between having a job and not. When there are no answers to check on the internet, how will you know you are right? We start to explore that here, and you can start to practice these techniques on your physics problems so you can get a better grade!

Exercises

Do Now!   Do these exercises immediately.

Not Now!   Do these after you start to forget the topic, say in a week.

More!   More exercises if you want. Maybe review before a test.

Required Problems

Optional Problems