Get Help with Vectors for New Physics Students

[dianajanielle]

New Member and Need help with a question

Hi. I am attempting to study introductory College Physics on my own so that when I find the time to go back to College- physics won't be so hard. I want to major in Math and Physics. Right now though, I am stuck trying to understand vectors. Could someone maybe explain exactly what they are. Thanks so much.

 

[civil_dude]

Vectors apply to many phenomena including force, velocity, acceleration and displacement. They have both magnitude and direction. When working with vectors, we use components to add and subtract them. The components are directed perpendicular to each other. You need to use trig to do the calculations.

 

[dianajanielle]

Thanks. Okay so now I know I need to use trig to figure out the question. I looked to the back of the book for the correct trig formula but when I put the numbers in the formula- I did not get the correct answer. All I can figure is that because I really haven't done that much trig, I am skipping a step.

So far I have this

A cross country skier skis 1.0 km North and then 2.0 km East.

Question
A= How far and in what direction is she from the starting point?

I have the correct answer for this part by doing
the Pythagorean Theorem.

the square root of 1.0 squared plus 2.0 squared which equals 2.24 km.

Next I have to find the tangent of angle 0 and this is where I am stuck.

the formula I am supposed to use is tan 0= y/x
The book that I am using has the answer as 63.4 degrees but I cannot figure how they came up with this answer. Please help!

 

[berkeman]

Welcome to PF. You may find wikipedia.org to be a valuable resource in your self-studies. Here is a starting page about vectors. You can also browse around wikipedia as other related topics come up.

http://en.wikipedia.org/wiki/Vector_(spatial)

 

[dianajanielle]

Thanks for your help! I have figured out the right answer.