# Magnitude and direction

## Homework Statement

Orv walks 312 m due east. He then continues walking along a straight line, but in a different direction, and stops 220 m northeast of his starting point. How far did he walk during the second portion of the trip and in what direction?
What is the magnitude?
What is the direction ___________ ° counterclockwise from the +x-axis

## Homework Equations

C=squareroot of 312^2+220^2
What equation to use to find direction??

## The Attempt at a Solution

C= Magnitude= 381.76 m why is my magnitude wrong?

Related Introductory Physics Homework Help News on Phys.org
A good idea here is to read the problem carefully, and/or make a simple diagram.
You're correct in using the Pythagorean theorem for this problem, but you're using it incorrectly. Remember that the form is a^2 + b^2 = c^2, where c is the hypotenuse.

In the problem statement, you're given a = 312 meters (The distance walked east -- one of the legs of the triangle), and c = 220 meters (The distance in a straight line from the starting point -- the hypotenuse).

This means that what you need to find here is b, not c.

As with regards to your direction issues, once you have your three sides figured out, use your trig laws (soh cah toa).

If you've never heard of them, it goes:
"soh" - sin = opposite / hypotenuse
"cah" - cosine = adjacent / hypotenuse
"toa" - tangent = opposite / adjacent

And you should get the right answer.
Cheers

EDIT: or your sin/cosine laws. I didn't work through the problem myself, I just assumed based on the level it was a right angle triangle.

EDIT: or your sin/cosine laws. I didn't work through the problem myself, I just assumed based on the level it was a right angle triangle.
Same. Now that I look at it (through my sleepy eyes), the 'hypotenuse' is shorter than one of the legs, and by a good bit, too...

I cant take the square root of a negative number for the magnitude... Is there another way to solve this...

## Homework Statement

Orv walks 312 m due east. He then continues walking along a straight line, but in a different direction, and stops 220 m northeast of his starting point. How far did he walk during the second portion of the trip and in what direction?
What is the magnitude?
What is the direction ___________ ° counterclockwise from the +x-axis
Did you ever draw it?

#### Attachments

• 8.2 KB Views: 403
@:AC130NAV: The problem states that the final position was 220 m from the starting point in an north easterly direction, so your drawing is not correct.

Last edited: