Putting It Together: Vector Addition

For many students who struggle with introductory physics, one of their main frustrations is that it seems like there are a thousand different problems in the course. One of the things you should concentrate on as you go through the course is looking for problems where you need to follow the same process to solve them. Though it may not seem like it, there will be numerous times throughout the semester where the problem you are working is fundamentally [latex]\vec{A}+\vec{B}+\vec{C}=\vec{R}[/latex]. You may need to add together three displacement vectors to find the net displacement or add together three force vectors to find the net force or add together three momentum vectors to find the net momentum of a system of particles. In each case, you will want to follow the process for adding vectors. And it is the same process regardless of the number of vectors you are adding together.

Vector diagrams make it easier to solve vector problems. Seeing what the vectors are in a problem can help us make better decisions about which coordinate system to use and minimize errors in breaking vectors up into their components. Train yourself to draw the vector diagram in a vector problem, even if you feel like it isn’t necessary. It also makes it easier to figure out where you are making a mistake. It may be that the error in your problem isn’t in the algebra, but it is because you have the wrong vector diagram.