Statics: Lesson 52- Truss Problem, The Combo Problem

Top 15 Items Every Engineering Student Should Have!

This video is NOT sponsored. Some product links are affiliate links which mean if you buy something we'll receive a small commission.

Please consider supporting the channel by subscribing, commenting, and liking each video. This moves these videos up the search list and helps me greatly. Thank you for watching.

This video is copyrighted by the Jeff Hanson for the private use of our audience. Any other use of this video or any pictures, descriptions, or accounts of the video without written consent from Jeff Hanson is strictly prohibited.

[zunaidhassan]

Like others, I'm getting CD = 2404.01 # (Tension), and CI = 3334.62 # (Compression). My calculation was as follows:

ΣFy = 0 = 1000 - (3606)Sin(56.3°) + (CD)Sin(56.3°)
=> (CD)Sin(56.3°) = (3606)Sin(56.3°) - 1000
=> (CD)Sin(56.3°) = 2000.03
=> CD = 2000.03/Sin(56.3°) = 2404.01 #

For evaluating forces in x-axis, CD sign will remain positive as it is tension.

ΣFx = 0 = (CD)Cos(56.3°) + CI + (3606)Cos(56.3°)
=> CI = -(CD)Cos(56.3°) - (3606)Cos(56.3°)
=> CI = -(2404.01)Cos(56.3°) - (3606)Cos(56.3°)
=> CI = -3334.62 #

[kylejohnson]

for those confused about point E only having a horizontal reaction force component. Point E is a fixed support. The only other force acting on point E is ED (either in tension or compression, regardless it is a horizontal force).Therefore, the only Reaction force possible from the fixed support at E is the Ex force that balances out the ED force.

[gavinliu]

for the joint C calculation, the CD should equal 2404 in tension and the IJ should equal 3333 in compression.

[georgesadler]

DR. Hanson, thank you for another awesome Truss and Combo Problem and their solution.

[manuboker]

Wonderful Statics lessons!! really taking the time to explain the problems along with a good sense of humor :))

[chrismarklowitz]

My answers I got:
FCJ = 3605.6 T
FCB = -1000 C
FIJ = -6000 C
FCI = -3333.3 C

What do others think I double checked my work and couldnt find a single thing wrong.

[hobeypollack]

Ahh he almost got his test question right! Second to last step! A+ on the explanation all the same.

[frankatuegbu]

CD=2404# T and CI=3335#C Please Jeff can you check

[gabewinter]

Can you come up with an ultimate problem that includes friction or a machine?

[forglory]

Isn’t the connection at E a fixed support? I thought fixed connections couldn’t be two-force members because they apply a couple?

[pentilex]

Could you also solve for the moment around A to find IJ?

[QuyenPham-ljzg]

At E, can we solve it as a fixed support with 2 reaction forces and 1 moment?

[sanny]

member CD is 2404 tension and CI is 3334 tension also.

[adhanommahray]

I got confused about how is that possible to eliminate the vertical force at point E

[terrancepage]

it looked like E was just a support with some kind of rope or line attached to the truss at D, so I was right to assume only a horizontal force there

[ImranKhan-tuix]

I am at problem no 10 right now and I will comment when I done all trusses problem than I will watch ur next machine and frame videos then I solve rest problems let's see how much time I take 26 dec 2021

[robertbone]

I might be mistaking but I think cb has the wrong sign.... otherwise I'm confused

[janiceowusu]

please can you do a video on solving space truss problems?

[kslane]

Mesa CC should just give my tuition to Dr Jeff Hanson

[gilbertonolasco]

What difference would it make if i cut thru the members vertically?