- First read the problem carefully enough so that you can state in your own words what physical situation is being described.
- Whenever possible, draw some kind of a diagram or simple picture of the physical situation. This is essential to the understanding of most problems. Trying to solve a problem mentally or intuitively usually consumes much time with no results.
- Explicitly write down what principle or law you think you ought to apply to the problem. Should you use Newton's second law, the conservation of energy principle or the conservation of momentum principle?
- Write down an equation that you belive applies to the problem. Ask yourself if the equation definitely holds in this particular situation. Are you sure that the quantities given in the problem are the ones given in the equation? For example, an equation may have a symbol for average velocity, whereas the problem gives an instantaneous velocity.
- If you cannot find a single equation that enables you to find the unknown quantity or quantities, write down all the equations you think you must use.
- Rewrite the equation(s) in symbolic form in such a way the the
unknown quantity or quantities are isolated. For example, suppose
that in step 4 above you decided that the problem must be solved by
Newton's second law:
*F*=*ma*If the unknown quantity you are looking for is

*a*, rewrite the equation as:*a*=*F/m* - The numerical quantities that have been given in the problem should
now replace their symbolic quantities in the equation. BE SURE THAT
THE UNITS ARE CORRECT. For example, when the MKS system of units is
used, the
__mass__of a body must be entered in__kilograms__and the__length__must be entered in__meters__. Be sure that the correct sign (+ or -) is used, particularly for quantities where sign indicates direction. The average student wastes many hours because s/he has been careless about using the right units or proper sign. - Calculate the unknown quantity. Does your answer appear reasonable--in magnitude and in units?
- Check your solution with the answer given in the text book.
- Go back to step 4 and see whether and how this problem clarified your understanding of a particular law or principle. Solving problems is only worthwhile if your knowledge of physics is deepened as a result.