Question

Help! Will give medals. Our teacher didn't go over this yet, I've been trying to figure it out for hours. And its due at 12am. I want to be guided through it, not answers.
(Vectors question)

Answer 1

The screenshot is the picture of the visual

Answer 2

Vector A has magnitude |A|=35.5, |B|=12.5 and |C|=32.2; angle are; thetaA=40(degrees), B=20 and C=15:

What is the magnitude A+B+C?
What is the angle between the positive x-axis and the vector, measured clockwise in degrees?
What is the magnitude of the vector -A+2B+C?
What is the angle between the negative x-axis and this vector, counterclockwise in degrees?

Answer 3

@phi

Answer 4

My teacher just went over this a few weeks ago. I can help, but give me some time to type my reply!

Answer 5

okay thank you!! she wasnt able to cover it all, and i understand vectors and the trig/geometry involved, but my answers arent working in

Answer 6

@x3_drummerchick I can't see any obvious sign of a diagram for your problem, which makes it a bit trickier to help.
Bon chance
http://perendis.webs.com

Answer 7

i posted an attachment in an above post ^

Answer 8

The way my teacher taught us to find the addition of three vectors is to use the head to tail method. Line the vectors up, the head (arrow) of one at the tail of another, and the resultant vector (the vector from the tail of the first to the head of the last) is the addition. I use a table to do this:

where the x comp and y comp are the x- and y-components for each vector.
Use the Pythagorean theorem and some trig (you said you knew how to do that) to find the x- and y-components of all three vectors. Then, in a final row for the resultant vector R, you add the x- and y-component values from the other three vectors (even if they're negatives, make sure to take the sign into account). Then, to find the magnitude:
\[\sqrt{x ^{2}+y^{2}}\]
That should give you a scalar for the magnitude of the resultant vector.
I know that was a pretty big word block, if you need more help definitely ask some questions!
(I don't think my drawing came out right...)

Answer 9

how do i find the x and y components for each vector, given that information? @SapphireMoon

Answer 10

i set up the table so far, but dont know what those values are

Answer 11

and thank you again for helping me!

Answer 12

For the A vector, \[\sin 40 = \frac{ opp }{ 35.5}\] where opp is the opposite side from when you learned trig, it's going to be the y component. you use algebra to rearrange it to \[opp = 35.5\sin 40\] . And it's the same for the x component, except that the x is the adjacent side so you replace sin with cos. That clicking? And don't mention it, I'm avoiding a physics lab...

Answer 13

oh wow, okay awesome! that makes a lot of sense. so with that said, after I find all the x and y components for A-C, what do i do?

Answer 14

@SapphireMoon

Answer 15

Add them up. Say for x components if you got -31 for A, 12 for B, and 13 for C, you'd add them to get -7 for the resultant vector's x component. (I haven't done the problem so I don't know the real numbers but do you get the idea?)

Answer 16

okay yes, that makes sense, thank you! so when they ask for the magnitude for }A+B+C|, do they want me to add up all those x and y components?