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## Homework Statement

Draw the vector [tex]\vec{C} = \vec{A}+2\vec{B}[/tex]

## Homework Equations

None

## The Attempt at a Solution

This is what i have i don't know if it is correct

P.S

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- Thread starter Paymemoney
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- #1

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Draw the vector [tex]\vec{C} = \vec{A}+2\vec{B}[/tex]

None

This is what i have i don't know if it is correct

P.S

- #2

tiny-tim

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No, that's not right.

When adding vectors, go to the end of the first vector,

- #3

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ok so is this what it should look like:

- #4

tiny-tim

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Put it back and start again!

- #5

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how i do this without bending it? So is it only meant to go horizontally?

- #6

tiny-tim

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how i do this without bending it? So is it only meant to go horizontally?

Yes, of course. And to the left.

- #7

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does it matter where you place the vector, because when i placed it in the middle it was incorrect??

- #8

tiny-tim

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(just got up :zzz: …)

so would this be correct.

Nooo …

I think I need to give you the answer:

To add two vectors, you must place the "tail" of the second vector against the "head" of the first vector: the sum is then the vector *to that point* (from where you started).

(or the other way round, of course: place the "tail" of the first vector against the "head" of the second vector: it makes no difference)

So in this case, you draw A which is an arrow going 4 to the right, then you draw B which is an arrow going 2 to the left,

(this is just like adding vectors to make a triangle, except that in this case the triangle is flat )

- #9

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ok, this is what i got from your explanation, so just to make sure i have interpreted your explanation correctly here it is again(hopefully correct -_-).So in this case, you draw A which is an arrow going 4 to the right, then you draw B which is an arrow going 2 to the left,and you draw that 2 starting at the end of the 4, so you end up with an everall vector of A + 2B being 2 to the right.

(this is just like adding vectors to make a triangle, except that in this case the triangle is flat )

yeh, I'm used to looking at the full triangle.

- #10

tiny-tim

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ok, this is what i got from your explanation, so just to make sure i have interpreted your explanation correctly here it is again(hopefully correct -_-).

I don't understand what you've done here.

Start on the axis, draw a blue line for A, then from the end of that draw a red line for 2B. Now draw a green line from the axis to the end of the red line (as if you were completing a triangle).

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ok here it is

why don't you draw it for me coz i don't think i'm getting anyway.

why don't you draw it for me coz i don't think i'm getting anyway.

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- #13

Mark44

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For the sum

Since all vectors involved here are horizontal, the sum will be a horizontal vector: one that points either to the right or to the left.

- #14

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What do you mean by "Now tack 2B on"?

- #15

tiny-tim

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What do you mean by "Now tack 2B on"?

- #16

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ok, i had another go at it, and this is what i got:

Last edited:

- #17

Mark44

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In the right diagram, the resultant (black) vector starts at the right place, but it's too short. In the left diagram, the resultant vector is the right length, but it starts at the wrong place.

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