# solving physics problems

Thus if rotation of the body and torque is in consideration, an indication of size and shape of the body is needed. That much can explain why not everyone goes for a physics career. The most important of those tools are the formulas. A ball of mass m and radius R with a uniform density starts rolling down a ramp (not necessarily flat) with no air resistance, no slipping. - The visual display of a graph is extremely helpful in seeing what is taking place with the variables in a problem. Comments: Alpha Solver uses the following convention: Up is positive. But for less common ones, it is helpful to know how to find the conversion factor: $\small{\text{Q}=\text{n}_1\text{u}_1=\text{n}_2\text{u}_2}$. After you become involved in physics, you will see it all around you, and you can begin to apply it to situations you encounter outside the classroom, just as is done in many of the applications in this text. Now that we have the unit vectors, we can express the vectors as the product of a magnitude and a direction. Important tips on solving physics problems (please read): Get your signs right. Mon français n'est pas assez bon pour savoir dire "WTF" , J'ai une collègue américaine qui vient de m'envoyer une recette de salade de fruits à la mayonnaise et je—, Flight attendant: Is there a doctor onboard? More emphasis on the topics of physics included in the SAT physics subject with hundreds of problems with detailed solutions. We thank the authors of the texts and the source web site that give us the opportunity to share their knowledge, Reflective Mental Overseer To draw a free body diagram, do not worry about drawing it to scale, this will just be what you use to help yourself identify the problems. Example: Any physical quantity can be expressed as a product of a combination of the basic physical dimensions. People often talk about physics as if it were merely a set of facts and equations: F=ma, energy can neither be created nor destroyed, E = mc², stars are giant balls of hydrogen fusing into helium and heavier elements, etc. CC licensed content, Specific attribution, http://en.wikipedia.org/wiki/Dimensional_analysis, http://en.wiktionary.org/wiki/trigonometry, http://en.wikipedia.org/wiki/Free_body_diagram, http://en.wikipedia.org/wiki/File:Free_Body_Diagram.png, http://www.youtube.com/watch?v=YocWuzi4JhY. The best way to do this is by fractions, but there are enough unit conversion guides out there that explain this concept. As long as you remember these formulas, you are most of the way to an answer. Whose cars go in which direction? Most of them shy away from physics problems, though, letting me – and a handful of other tutors – deal with the dreaded subject. It is much more powerful than memorizing a list of facts. Velocity: The velocity of moving object is modeled by a vector whose direction is the direction of motion and whose magnitude is the speed. Describe the process for developing a problem-solving strategy. - A frame of reference could also be moving. After plotting the equations one can sometimes just look at the graph and "visually figure out" the answer. What is the electric field a distance r away from an infinitely long line of charge (i.e. This gives you two directions to explore: (a) going back through the mathematical steps of your solution to see if you can find any mistakes or (b) going back to the starting principles you employed to solve the problem that generated the equation you were using. - Leave all knowns as symbols and solve for any unknowns as an equation in which the "unknown = expression of the knowns", one equation for each unknown. So we’ve tried to construct a method of attacking general physics problems. Normally xo = 0 if you place the origin at the initial location of an object. If your question asks for minutes and your answer is in seconds, you missed a step. Add your input in the comments! For example, if you do not enter all the known values in SI units, then your computer will give you a number but it will not be dimensionally correct.