Hints & Approaches for Solving Physics Problems

المادة الدراسية: 

Hints & Approaches for Solving Physics Problems
 

  • Read the problem very carefully a couple times.
  • Draw a picture of the problem.
  • Determine the dimensions of the problem.

For example, is it 1-dimensional, 2-dimensional, or 3-dimensional?

  • Pick positive (+) directions for each dimension.
  • Write down all of the given data and information.

For example, mass, velocity, time, charge, voltage

  • Write down what is being asked for.

For example, velocity, acceleration, electric field

  • Think about the involved physical concept(s).

For example, uniform acceleration, Newton's Second Law, Conservation of Energy, etc.

  • Write those concept(s) down!
  • Look up the equations relevant to the concept(s) involved.
  • Combine equations, make substitutions, and solve for the needed variable.
  • Convert all units into System International (SI) units.
  • Plug the numerical data into the equations and solve for the answer.

 
 

Reality Check!

  • Does answer make sense?

For example, you can't have a velocity greater than the speed of light,3 x108 m/s.

  • Check the units. Are your final units in the units of the parameter sought?

For example, if you are looking for a mass, is the answer in terms of kg,or m/s?

  • Check the limits of your answer if you have a formula as an answer.

For example, a charged disk acts like a point charge at an infinite distance.

  • Plot your answer, if you have a formula as an answer.
  • Do the limits and zero crossings make sense?
  • Eliminate unphysical solutions.

For example, an exponential growth as a function of time for a damped harmonic oscillator.

  • Box your answer.

All of these points will help your mind think through the problem. If you do not draw a picture, you are forcing your mind to tie up brain cells conjuring up the image. If you do not write out the data in the problem, you cannot really see the entire problem.
If you cannot get the problem, following the above steps will demonstrate that you are thinking about the problem and hence makes you eligible for partial credit.