Find all three components of vector W

[Toranc3]

Homework Statement

W is 8 units in the y-z plane in a direction defined by theta = 120 degrees with respect to the y-axis and have a positive z component.

Homework Equations

Wy=Wsin(theta)
R^(2)=Rx^(2)+Ry^(2)+Rz^(2)

The Attempt at a Solution

Wy=Wsin(theta)
Wy=8sin(120) =6.9

8^(2)=Sqrt(0^(2)+(6.9)^(2)+(Rz)^(2))

Rz=4.04 units. is this par right? I am not sure how to approach this one. I only how how to deal with x and y-axis but not z. Can sombody point me in the right direction? thanks!

 

[voko]

x, y and z are just labels. What is important is that you have two axes and a vector in their plane, at an angle with respect to one axis.

 

[Toranc3]

x, y and z are just labels. What is important is that you have two axes and a vector in their plane, at an angle with respect to one axis.

Would I use y or z with the cosin(theta)? How do I know to what goes with sin and cosin?

 

[voko]

What is the angle with respect to? What do cosine and sine mean? Draw a unit circle, and label the axes with y and z so that things make sense.

 

[Toranc3]

What is the angle with respect to? What do cosine and sine mean? Draw a unit circle, and label the axes with y and z so that things make sense.

Thanks!