# Homework Help: Science Fair Project involving Vectors

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1. Nov 2, 2014

### Maggie Tarmey

1. The problem statement, all variables and given/known data
My science fair project (high school sophomore) is about calculating the amount of force that is sustained from a fall off of a horse at different heights at different gaits (speeds). I would then compare the force sustained in the fall and compare it to what certified helmets are qualified to protect against and see if they offer enough protection to the skull. My old science teacher recommended that I research vectors, and that was how I would be able to calculate the force.
However, everything about vectors that I find is very far over my head. I was wondering if anyone here could either show me a link or explain to me in a dumb ed-down way what exactly vectors are, how to calculate the force from them, and what data I need to gather (if I need any more) in order to be able to calculate the force. My current science experience was last year's (honors) combination of Earth science and very basic physics and the beginning of this year's honors chemistry course.

2. Relevant equations
I'm looking to learn how to calculate vector forces, so whatever equation(s) are used for that I suppose?

3. The attempt at a solution
I've asked my science teacher from last year, and all he told me was to research vectors. Everything I found was way over my head so I'd like to know if there is a certain website or video where it is simplified to an easier to understand level.

2. Nov 2, 2014

### elegysix

a vector simply describes the magnitude and direction of a thing (in your case a force), whereas what you are probably used to are called scalars, which is just the magnitude of the thing.
For instance $F=3\hat{i}$ N is a vector.
This says the force is 3 N in the $\hat{i}$ direction, whereas just saying $F=3$N is a scalar, and that force could be in any direction.

You can find an explanation of some basic operations with vectors here: http://www.mathsisfun.com/algebra/vectors.html

I imagine you will have a difficult time getting any kind of acceptable accuracy through calculations alone. It would probably be easier and more accurate for you to do an experiment.

Here's my advice for such a thing - buy an accelerometer, cantelope, and a helmet. Weigh the cantelope/helmet/accelerometer together. Put the cantelope in the helmet with the accelerometer, and drop it from head height while riding at different speeds. Then use F = m*a and calculate the maximum force during the initial impact for each trial.

3. Nov 3, 2014