Other times, there will be variables whose purpose is revealed in a later part of the question.
However, the more you use the formulas, and the more you understand what they mean and – if you care enough to check – where they came from, the easier it gets to remember them. If you have a cheat sheet, align it next to your variables. In fact, in the vast majority of questions, no matter what equation you use – assuming that it is relevant to the subject matter, and that you insert the proper variables – you will reach a solution.
What formula can you fill up, leaving the least amount of missing variables? The way to know which equation to use depends on two main issues: the variables given to you in the equation and your experience.
Some professors will require that you memorize relevant formulas, while others will give you a “cheat sheet.” Either way, you have what you need.
Memorization might sound horrible, but most physics subjects don’t have that many equations to memorize. Physical equations didn’t just land on scientists from the sky, all wrapped up nicely in mathematical formulation.
This will help you see the variables in front of you clearly, find the proper equation to use, and see what you’re missing.
It will also make the original, confusing text unneeded.
For example, getting a visual idea of your frame of reference, or of the difference between up (positive) and down (negative), can mean the difference between a right answer and a wrong one. Go on, Picasso, give it your best shot, and move on to the next step.
Sometimes your professor will test your unit conversion skills.
Read the question carefully – this isn’t the time to skim. Word problems are confusing only because they hide the actual variables inside them.
Sometimes, you will be given extra information that you won’t really need.