Help with adding vectors with component method (sin/cos/tan)

In summary, the ship is 30 units above the x-axis, 50 miles north of west, and 60 degrees east of north.
  • #1
amd123
110
0

Homework Statement


A ship leaving its port sails due north for 30 miles and then 50 miles in a direction of 60 degrees east of north. At the end of this displacement, where is the ship relative to its port?

An army recruit on a training excercise is instructed to walk on a bearing of 6.3 degrees north of west for 5 miles, then on a bearing of 41 degrees north of east for 4 miles, and finally on a bearing of 15 degrees west of north for a direction of 3 miles. Determine the distance and direct the recruit must walk to return to his starting position?



Homework Equations


What is the difference between let's say North of West and West of North and how does this make my drawing of the triangles different? Because for these two problems my teacher said I have my x and y values reversed because of how I drew the triangles because of the description of the direction.

I know I'm doing the sin/cos/tan functions correctly but I get my values in the opposite places X for Y and vice versa because of the north of west and west of north concept.

Can someone please explain it to me?



The Attempt at a Solution


http://img231.imageshack.us/my.php?image=77107532lx7.jpg
http://img231.imageshack.us/my.php?image=74381618jo2.jpg
according to my teacher my answers are wrong... what am i doing wrong?
 
Last edited:
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  • #2
amd123 said:

Homework Statement


A ship leaving its port sails due north for 30 miles and then 50 miles in a direction of 60 degrees east of north. At the end of this displacement, where is the ship relative to its port?

An army recruit on a training excercise is instructed to walk on a bearing of 6.3 degrees north of west for 5 miles, then on a bearing of 41 degrees north of east for 4 miles, and finally on a bearing of 15 degrees west of north for a direction of 3 miles. Determine the distance and direct the recruit must walk to return to his starting position?



Homework Equations


What is the difference between let's say North of West and West of North and how does this make my drawing of the triangles different? Because for these two problems my teacher said I have my x and y values reversed because of how I drew the triangles because of the description of the direction.

I know I'm doing the sin/cos/tan functions correctly but I get my values in the opposite places X for Y and vice versa because of the north of west and west of north concept.

Can someone please explain it to me?



The Attempt at a Solution


http://img231.imageshack.us/my.php?image=77107532lx7.jpg
http://img231.imageshack.us/my.php?image=74381618jo2.jpg
according to my teacher my answers are wrong... what am i doing wrong?

Let's say that the x-axis runs in the E-W direction and the y-axis in the N-S direction. Then, 30 miles north of west would be 30 units above the -x axis, with the angle between the line connecting the origin and the point and the -x axis being your desired angle.
 
  • #3
there i posted my work
 

1. What is the component method for adding vectors?

The component method for adding vectors involves breaking down each vector into its horizontal and vertical components, then adding the components separately to find the resultant vector.

2. When should I use the component method for adding vectors?

The component method is useful for adding vectors that are not in the same direction, as it allows for easy addition of their horizontal and vertical components.

3. How do I determine the direction of the resultant vector using the component method?

The direction of the resultant vector can be determined using trigonometric functions, such as sine, cosine, and tangent, to find the angle between the resultant vector and the horizontal axis.

4. Can I use the component method for adding more than two vectors?

Yes, the component method can be used to add any number of vectors. Simply break each vector down into its horizontal and vertical components, add the components separately, and then combine the resultant horizontal and vertical components to find the resultant vector.

5. Are there any limitations to using the component method for adding vectors?

The component method may not be the most efficient method for adding vectors in some cases. It also requires knowledge of trigonometry and may be more difficult to use for vectors with non-integer components.

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