Recent content by ian_spurlock

And thanks @ Subdot I'll remember that trick from now on

OK that makes crystal clear sense. I feel kinda dumb for not thinking of that haha. Looooooooong day. :epic facepalm: Thanks a lot man. Much obliged.

OK great. I'd like to know how to solve this in case I encounter a problem like this on an exam.

The answer was 119 apparently. I don't even know why. Maybe my sketch is just extremely difficult to interpret? Blah. Anyway, thanks for the time and input. At least I have the raw calculation part down. Thanks a bunch.

Eh, I am bad at sketching in 3d. What can I say about it really? It's below the XY plane? Exactly what is theta in this case?

I'm bad at sketching 3d and I really don't know how to interpret my sketch.

It's a multiple choice problem with the choices being: 90 119 151 61 29 I've already tried 2 answers, forfeiting 50% of the potential credit. Is it possible that it is 151 degrees? That is 61+90 degrees... Or 119? 180 - 61? God I hate Mastering Physics. They gave us a free trial for it as...

A = 2i - 2j - 3k ... A = 4.12 j = 0 + 1j + 0 ... j = 1 |i j k | |2 -2 -3 | |0 1 0 |... this matrix yielded N = 3i + 2k ... N = 3.61 N = Aj sintheta theta = sin^(-1) (N/Aj) = 61 degrees

I tried to solve it as such... and I got 61 degrees which was wrong...

Ahh, of sintheta I'm getting it now. Is j = (0i -2j + 0k)? Is it as simple as that?

That part I do know how to do. But if I crossed vectors A and j, wouldn't I just get a vector in some form of i + j + k? How would I calculate an angle from that?

Well like vela posted the cross-product formula is LaTeX Code: |\vec{A} X \vec{B}| = |A||B|sin \theta But I only have a vector A? Or can I use components of vector A in that formula?

To be honest, I don't know what formula to use and I don't even know if I can use the y-axis as a vector. I don't want the answer... I just want to know where to start and what procedure I should use. I'm pretty confused.

How to find the angle between an XYZ vector and the y-axis? Please help! Homework Statement A vector is given as follows: A = 2i - 2j - 3k The angle between A and the y-axis is, in degrees, closest to?: 90 119 151 61 29 Homework Equations c = ab sin\theta ? The...