Components of a vector - don't know what I am doing wrong

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Homework Help Overview

The problem involves two medical teams on a reconnaissance mission, with their positions described in terms of distance and angles relative to a base camp. The original poster is tasked with finding the distance and direction of one team from the other using vector components.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate the resultant vector using component addition but expresses confusion over the correctness of their approach. They question their understanding of angle measurement and the application of trigonometric functions in a non-right triangle context.

Discussion Status

Participants are actively engaging with the original poster's calculations and assumptions. Some suggest that the formulas used may not be correct, while others encourage the use of diagrams to clarify the situation. There is an acknowledgment of potential misunderstandings regarding angle measurement and vector addition.

Contextual Notes

The original poster mentions struggling with direction and the lack of a right angle in the triangle formed by the teams' positions, which complicates their calculations. They also indicate a need for geometry rules to assist in their understanding.

Hemingway
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Homework Statement



Two medical field teams set out for a reconnaissance mission and lose one another. The GPS at their original camp shows the location of the first medical team as 43 km away, 15° north of west. The second medical team strayed 32 km away, 33° east of north from base camp.

When the first team uses its emergency GPS to check the position of the second team, what does it give for the second team's (a) distance from them and (b) direction, measured from due east?

Homework Equations



Rx = ax + bx
Ry = ay + by
a2 + b2 = c2
tan -1 = opp/adj

The Attempt at a Solution



ax = cos 15° x 43km
= -41.53km

ay = sin 15° x 43km
= 11.13km

bx = sin 33° x 32km
=17.42

by = cos 33° x 32km
= 26.83

Rx = ax + bx
= -41.53km + 17.42km
= - 24.11km
(or if we take positive direction of x the other way)
= +24.11km

Ry = ay +by
= 11.13km + 26.83km
= 37.96km

Rx2 + Ry2 = Rhypotenuse
= \sqrt{}-24.11<sup>2</sup> + 37.96<sup>2</sup>
= \sqrt{}2022.3
= 44.97km

tan-1 = opp/adj
= 57.6°

both answers were wrong. I cannot see what little mistake I am making
 
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Sorry about code problem, hopefully you understand what I mean. ignore the 'sup'
=√( 24.11 ^2 + 37.96^2)
= √(2022.3)
= 44.97km
 
Yeah, it's clear. You're just mixing up the LaTeX and BBcode syntaxes but we're kind of used to both around here :wink:
Hemingway said:
Rx = ax + bx
Ry = ay + by
Take a close look at those formulas. They're not correct. (Hint: if a and b are the same vector, what should you get for R?)
 
Okay so I worked out that Rx = ax + bx but ignored the Ry as it wasn't required, turned out to be correct. So thank you for that.

My only drama at this point is the angle for east. I apply an axis for direction at team A and look for angle at east. I wish I knew how to diagram this on here. But basically incorrectly assumed the east angle is the angle at the left vertice of the triangle, And since the I am not sure if this is a correct assumption. I struggle with direction sometimes. There is no right angle so I cannot do that, so need geometry rules am I correct-ish??
 
Sorry that was a brain dump. I cannot use inverse tan /cos/sine here as it is not a right angled triangle correct? and is my assumption of measuring the angle from team A's corner of triangle correct? Thank you so much by the way!
 
Hemingway said:
Okay so I worked out that Rx = ax + bx but ignored the Ry as it wasn't required, turned out to be correct. So thank you for that.
Did you notice I said the formula Rx = ax + bx was incorrect? If you got the right answer using that formula, it was completely by accident.
Hemingway said:
My only drama at this point is the angle for east. I apply an axis for direction at team A and look for angle at east. I wish I knew how to diagram this on here. But basically incorrectly assumed the east angle is the angle at the left vertice of the triangle, And since the I am not sure if this is a correct assumption. I struggle with direction sometimes. There is no right angle so I cannot do that, so need geometry rules am I correct-ish??
But you can draw a right triangle :wink:

If you can draw a picture of what you're talking about using some image editor, you can attach it to your next post. I think that might help.
 
diazona said:
Did you notice I said the formula Rx = ax + bx was incorrect? If you got the right answer using that formula, it was completely by accident.

But you can draw a right triangle :wink:

If you can draw a picture of what you're talking about using some image editor, you can attach it to your next post. I think that might help.

Ah, damn it. I did see that but obviously I was misled by the fortuitous accident :) I got the angle wrong obviously so I have been given a new set of numbers now for the problem. I will post my working, images and ideas a little later after I go to work.

Thank you so much for your assistance diazona, I really very much appreciate you taking the time and patience :)

H.
 

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