## 20130709

### Physics presentation: vectors

"Physics majors, architects, engineers, and, uh, other people--lend me your ears, I have come not to bury vectors..."

"...but to praise their trigonometric sensibilities!" Eh. Boring, yes, but important.

Briefly, given the magnitude and direction of a vector, the cosine and sine trigonometric functions allow the x- and y- components of a vector to be calculated.

Conversely, given the x- and y- components of a vector, the Pythagorean theorem and the inverse tangent trigonometric function allow the magnitude and direction of a vector to be calculated.

Note that there is a fair amount of care to be taken in determining the right ± signs and angles here, as not all vectors are conveniently going to be located in the first quadrant. Caveat geometer.

Don't be this student. If all this seems familiar to you, then fine, make sure you review it before we move on to projectile motion. If all this makes you uncomfortable, or worse yet, seems unfamiliar, then you have a lot of work to do.