First thing which student should do before doing the physics Problems is the study of the chapter and concepts

## Studying the Chapter and Concepts

**(1)** Attend all the classes in School and understand whatever the teacher is saying about the chapter.

**(2)** Take good notes and develop the concept.

**(3)** When you copy drawings, completeness is worth more than careful artwork. You should not only copy what is on the board but also record important points that the teacher makes orally about the diagram.

**(4)** Study the chapter at home also, and if you have any doubts, ask the teacher and friends.

**(5)** Write down important formulae and important concepts in the chapter as it helps in revision and solving questions.

**(6)** Ask yourself honestly if you truly understand the concept and are ready to take on the problems. If not, I would advise revisiting the chapter again.

## Understanding Solved Examples

Now that you have understood the chapter, it’s time to pay attention to solved examples and get a way of solving the problems. Read the solved examples several times until it makes sense to you. Learn the way the solved examples are solved. After these two things are completed, we are ready to plunge into the problems.

## Solving Physics Problems

**(1)** Don’t panic. Stay cool and have confidence that you will be able to solve the problems.

**(2)** Read the problem carefully and understand what is being asked and try to link it to the concept you have understood in the chapter. If you don’t understand the problem the first time, then read it again. Sometimes the wording of the problem may be tough, but the question is simple. So you need to develop the attitude to carefully read the problem and understand it quickly. It may take time initially, but soon it will become a habit.

**(3)** Draw a clear diagram showing all the systems and interactions between them. For mechanics problems, free body diagrams provide immense help in solving the problem. Problems will become easier once they are drawn out. For electricity problems, drawing the resistors in series and parallel will help.

Drawing a clear diagram in physics problems is very important as it helps in understanding the problem and makes the solving process easier. Many times, drawing a good diagram is even important for getting good marks.

**(4)** In any physics problem, some information is given, and the value of some variable is to be found. Jot down all the known quantities on one side and list all the unknowns for which you are solving the problem on the other side.

**(5)** You must use a consistent system for all the quantities involved. This will ensure you get the correct answer. Suppose you have initial velocity in km/hr and final velocity in m/s, then it makes sense to convert them into one unit. At the same time, if the physical quantities given are in km/hr, then it is needed to convert them into m/s for the sake of conversion.

**(6)** Establish which general principle relates the given parameters to the quantity that you are seeking. Usually, your picture will suggest the correct method and formulae.

Write down relevant physics principles and identify physics equations that might be useful, particularly those that link the values given in the question with those that you are looking for. If the problem is around uniform motion in one dimension, we know that the following formulae will be used:

$v^2 = u^2 + 2as$

$s = ut + (1/2)at^2$

$v = u + at$

**(7)** Take your formula and try to solve for one variable at a time. Solve for each variable that is listed under the “unknown” category. Try to solve for variables that you can determine easily first. We need to remember we should have as many equations as many unknown variables.

**Here are some tips for this:**

- Do neat work so that things do not get messed up in between.
- Distinguish between vector and scalar from the start and write proper notation and sign convention.
- Use proper variables and keep them consistent till the end. It will help in doing the final calculation at the end.
- Don’t use the same letter twice for different values in the same question.

**(8)** Break down the large problem. Sometimes the problem may be big, and it will look scary. In these scenarios, it is easy to divide it into pieces and then solve it, linking each piece together.

**(9) **Finally, check if the result makes sense to you.

- Following techniques can be used to check the correctness of the answer:
- Numerical reasonableness: If you need to find the mass of a person, then 1000 Kg will be unreasonable. If you’re working out a speed and reach a value greater than the speed of light, you know something has gone wrong.
- Dimensional analysis: Suppose you get some answer in terms of some known physical quantities and constants. You should be able to perform dimensional analysis of the answer to check its correctness.
- The result obtained should hold good for special cases and limiting values. So, does your answer give the expected values for extreme situations, such as when a quantity goes to zero or becomes very large?
- Functionally reasonable: Many times, the formula you receive as an answer can be checked using common sense. You may need to ask, “Does your answer depend on the given quantities in a reasonable way?” Suppose in the case of a sound problem, you know that if the object comes near you, you will hear a higher frequency, and if it is going far from you, you will hear a lower frequency.
- Always specify the result with units. If it is a vector quantity, then please specify the direction also.

**(10)** Master these techniques in physics homework, then you should be able to finish your physics examination within the given time and with no mistakes.

## Concept Map

Here is the concept map on the above article on how to do physics problems:

* Do not miss this short presentation on how to memorize physics formulas*.