Solving problems – the best way to learn physics
Problems solving activity will help you to understand physics laws. The more problems you solve the better your understanding of these laws. There are some general rules on how to solve problems and it is a good idea to familiarize yourself with them. We will give you a short list of these rules.
1. Read the problem carefully and try to understand it, that is, answer yourself the following questions:
- what experiment would be possible to solve the problem experimentally. In other words, what experiment or phenomena is involved in the problem?
- what is the question you are supposed to answer?
2. Identify the physical laws, principles, and equations involved in the problem. Write down these equations.
3. Make a graph, sketch, or drawing to visualize the situation described in the problem.
4. List all quantities involved in the problem and assign symbols to them IF THEY ARE NOT assigned in the problem text.
DO NOT solve problems using numbers right away, even if the problem is very simple. Always first solve problems analytically, that is using symbols.
5. Once you have solved the problem analytically make the first check by substituting units to the final equation.
- If you do not get the correct dimension for your answer, the solution is definitely wrong.
- If the dimension of the quantity you are looking for is correct, the solution may be correct.
In case a. start from the beginning.
In case b. make further checks by, for example substitute numbers given in the problem and see if the result is reasonable. If the speed of a car obtained from solving the problem is 10,000 km/h - something definitely went wrong during the solving.
When you solve 200, 300 problems in physics you will develop methods for checking the correctness of the answer. It is like learning to swim. It is easer with an instructor, but no one, no book, no manual, can teach you. You must learn it yourself.