Recent content by jernobyl

Okay, well, erm, I've done it parallel and normal to the plane. Resolving along the plane: 0 + Tcos15 - 10g.sin30 = 0 And perpendicular to the plane: N + Tcos15 - 10g.cos30 = 0 I don't even know if that's right or not. I wish I just understood.

Hello? Anyone? :(

Oh! Oh, I see. Okay, thanks! Um...I couldn't trouble you to look at my other coplanar force, could I? ;)

Homework Statement A uniform beam AB of length 6m and weight 11 N rests horizontally on two supports C and D, where AC = 1m and DB = 2m. Weights of 6 N and 7 N are hung from points A and B respectively. Calculate the reactions at each support. What extra force must be applied at B in order...

Thanks for your reply, Dick, but err...I'm not entirely sure what you're saying. The "cancellation" of the horizontal and vertical components? I'm not following...

Homework Statement This is from exercises on Coplanar Forces and Moments. A particle of mass 10kg rests in equilibrium on a smooth plane inclined at 30 degrees to the horizontal, being held by a light string inclined at 15 degrees to the line of greatest slope of the plane. Find the...

Hi, um, if "row reduction of the augmented matrix" can also be called "elementary row operations" (as I'm reading in my notes) then yes, we have learned that, but it was kind of forgotten about, being hailed as a long-winded and quite inefficient way of finding the inverses of matrices, and...

And you know what? That solves the whole thing. I knew it. One sign off. Thanks so much for noticing, I'd never have gotten it! I need to go be dead now. :S

Homework Statement Express the following equations in the matrix form AX=B. Determine the inverse of A and hence solve the equations. 4x-3y+z=11 2x+y-4z=-1 x+2y-2z=1 Homework Equations Not really applicable. The Attempt at a Solution A bit of background, this is for a...

Yeah, thanks. I'm just not sure, like...one of the answers to one of the questions was -7.15 degrees...and how can that be, if you're meant to measure it counterclockwise from the positive real axis? Sigh.

Ah, thanks for that. I'm confused but I kinda understand the answer...

Thanks for this. The exercises I have been doing on complex numbers have all asked for the principal argument, and some of the answers are not between \pi and -\pi, such as 239.04 degrees. Okay, err, I've plotted -i on the argand diagram...-i is at "-1"...I'm really not getting it here...

Homework Statement Express -i in polar form, using the principal value of the argument. Homework Equations modulus = \sqrt{a^2 + b^2} \theta = arg(0 - i) The Attempt at a Solution Well, the complex number is 0 -i. a = 0, b = -1 so: r = \sqrt{0^2 + (-1)^2} which comes out to...

There should be a dt at the end. Okay, split it up into the threee terms and integrate. Fine. What IS integration by parts?

Okay, to be honest guys, this is starting to drive me mental, I've been working on it for an hour and I've gotten absolutely no-where. I've changed the variables and this is where I am. I don't even know if this is right. Having substituted (wt + A) for a, and (2wt + B) for b...