Recent content by billmccai

Homework Statement We were provided with the dimentions and specifications for a highway sign, and given assumptions for weight and wind forces acting on it. Firstly, we had to calculate the reactions at the base. And then draw stress blocks and Mohr's circle for four points on the base of...

Still not following. My load impedance is 8 + 3j, right? I understand that I need to get rid of the imaginary part.. i just don't get how I mathematically determine the correct C value. I know it's going to be -(something)j ohms. But how to i manipulate Zcorrected load = [Zc * (Zr + ZL)] / [Zc...

I'm meant to bring the pf to unity at the load only, so I'm assuming i just forget the line impedance for now. In this case, i thought Zr + Zl just referred to (8 + j3), which is my load impedance. I don't know how to work out what value for Zc will cancel out the imaginary part in the formula...

Homework Statement This is the circuit: http://img129.imageshack.us/img129/3566/pfcog8.jpg Assume voltage is in rms and f is 50Hz. I have to do three things. First, calculate and compare true power vs apparent power in the load. Second, find the value of a capacitor placed in parallel...

Sorry. It just seemed from his post that he hadn't (or wasn't present when they taught it), so thought doing the first part would help give him the idea.

When in three dimensions, there are actually six equations of equilibrium (three in 2D). You have moment equations about each axis direction. Note that you can solve mathematically without looking at it about each axis, but it just makes it easier sometimes to break it up into components (like...

Homework Statement Find dy/dx for: a) xsin(xy^2) - ln(x/y) = y b) x = 3cos(a), y = 2sec(a). simplify then find dy/dx when a = pi/3 Homework Equations The Attempt at a Solution I've done both of them, was just hoping someone could check I've done things correctly. I'm...

Homework Statement A water tank is in the shape of an inverted conical cone with top radius of 20m and depth of 15m. Water is flowing into the tank at a rate of 0.1m^3/min. (a) How fast is the depth of water in the tank increasing when the depth is 5m? Water is now leaking from the...

Yay. :smile: hey ho let's go.

Found my error (again). My maximum amount for D was 1 2/3.

My mistake. I think A should be 45 + (7 1/2)t. That's what I was thinking for part (c) but wasn't entirely sure. It makes sense now. Thanks again for your assistance. You've been extremely helpful.

Thanks so much for your help. I've done as you said and ended up with: A = 16 2/3 + (7 1/2)t B = 10 - 6t C = 6 8/17 - (3 3/17)t D = t Does this look about what I should have expected? Also, any advice as to answer part (c) from this information?

Oh ok. So my amounts of brands A, B, and C, are going to end up being given in terms of t?

Homework Statement A fertiliser company sells four types of lawn fertiliser. Brand A 24-4-8, Brand B 21-7-12, Brand C 17-0-0 , Brand D 0-12-12. The three numbers refers to the percentage of nitrogen, phosphate and potassium in that order contained in each brand. Suppose that each year...