Question

You are given a vector in the xy plane that has a magnitude of 90.0 units and, a y component of -41.0 units. Assuming the x component is known to be positive, specify the vector, V, if you add it to the original one, would give a resultant vector that is 89.0 units long and points entirely in the -x direction.

Answer 1

Okay so the previous question to the one I'm confused on asks me to find two possible answers for this vector's x component which I got -80.1,80.1 using the pytheorem's therom. For this particular question, if I'm being asked to get a direction that points in the -x direction how is that going to be possible if the x component is assumed positive?

Answer 2

You are given a vector in the xy plane
that has a magnitude of 90.0 units
and, a y component of -41.0 units.

Assuming the x component is known to be positive, specify the vector, V,
if you add it to the original one,
would give a resultant vector that is 89.0 units long
and points entirely in the -x direction. <-89,0>

Answer 3

So that vector V would be -89?

Answer 4

V would be what we add to the first part to get to <-89,0>

Answer 5

<a,-41>
+<x , y >
-----------
<-89, 0>


y = 41 in this case; we just need to determine a and x

we can do a from the pythag thrm; we know: 90^2 = 41^2 + a^2

Answer 6

a^2 = 90^2 - 41^2

a = sqrt(90^2-41^2)

x+a = -89, so x = -89-a

x = -89 - sqrt(90^2-41^2)

Answer 7

gotta make sure i did that right :)

Answer 8

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=-89+-+sqrt(90%5E2-41%5E2)

Answer 9

<-169.12 , 41> might be our V vector

Answer 10

doesnt make sense to me for some reason

Answer 11

unless this formula is reading a over in quadrant 4 instead of quadrant 3

Answer 12

<-8.88, 41> looks better from my drawing