2014 NCEES Problem 515

[ASchmidt]

Problem states: "A compound curve is shown. The length of the radius of the second curve (R2) is"

Working through the solution, I am struggling to figure out how delta2 was determined. Delta2 = 1.25 + 30.75 = 32d

Can someone please explain this, I am sure it is something very simple....thanks.

 

[John QPE]

I should really figure out how to scan and upload images, but if you shoot me a message I can email this to you

The way I do this is to draw in the X,Y axis, and extend the lines through the opposite quadrant.

S 59*15'E when extended gives you an angle of 59.25* from the Y axis and 30.75* from the X axis

N 88*45'E when extended gives you and angle of 88.75 from the Y axis and 1.25 from the X axis

So you have an angle opposite D2 of 32* (30.75 + 1.25)

Shoot me a message if this doesn't make sense, and I'll send you my scratch work and it will become obvious.

 

[ptatohed]

hmmm... this prob isn't in the 2011 NCEES Sample Q&Ss, is it? I don't think I have seen/worked this one. Is it possible to post the whole problem?

 

[ptatohed]

Ok, I finally got around to solving this one. AS sent me the problem a week or two ago. I get answer B. I first solved for T1. Then T2 = 2000 - T1. Then it is simply R2 = T2 / Tan(I2/2). Is this how you guys did it?

 

[John QPE]

I didn't work the entire problem, I just helped with the d2 solution, but yeah ..... what you did is what I would have done.