Statics: Lesson 53 - Frame Problem with 2 (Two) Force Members

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[aminesalame]

Can we just appreciate the Professor’s sick drawings.

[UzsDcUZ]

This guy is hillarious and he chill, this manz chill frfr. Thank you so much, you make a difference

[MsLegobuilders]

my google search history:
why is statics so hard?
Can you finish a frame question in under 20 minutes? (my quizzes are 20 minutes)
Frame problem shortcuts

in conclusion, there are no shortcuts and my professor is wildin

[NiemanScott]

Professor, at 9:30 you said "the sum of the forces at that pin have to be zero". It makes so much sense the moment you said that so many things clicked! I have been struggling so much because I wasn't flipping the directions. I don't know if neither you or my professor never explicitly said that, or assumed it was obvious, or I never heard it before - but for me that was the missing link. Thank you very much!

[markcoleman]

Jeff Hanson, that was one of the finest statics problem solutions I've seen in a long time. Yeah, one minor mistake on Fab, but that was NOT an issue. In fact it added credibility!
The process was just stellar!
Well done. You have a great teaching style! Keep it up.

[ciamaechamae]

got confused on the distances for moments & triangles mainly because of the complex measurements but Mr. Hanson's way of teaching is so effective
Fab= 1750#
Cx= 193.75#
Cy= 2422.46#

[travismcintosh]

"Here's the base, it's all about that". Thanks for the occasional humor while teaching Dr. Hanson.

[vinaysheshadri]

At 27:31, Fab is not 875lb. It is actually 1750lb.

[StevenLinehan-xe]

Dr. Hanson's book has points E and G on the same horizontal line. Both are 10' above the ground. The distance from the ground to point C is 5.483. Therefore, the distance from point C to E is 10 - 5.483 = 4.517. The Fex moment calculation, according to his book, should be 376.8 lb (cos59.06)*4.517.

[keatonmcintyre]

These videos are the best but just one correction. To skin a cat refers to catfish. When cleaning catfish you have to skin them, unlike most fish. Just a fun fact! Can't wait to use these videos in dynamics!

[patrickkearns]

This is my first comment on YouTube, and it is to say that Mr. Jeff Hanson is the GOAT!

[kensonmalupande]

This example is extraordinary, thanks for the Solid explanation, professor.👍

[yingtongluo]

Thank you for creating this. It really saves my midterm exam!

[benno]

Note, I am quite sure there are a few errors on this problem. Here are my calculations. (Take it with a grain of salt, but test for yourself).

The main problem is that the angle which jeff used as 59.06 degrees on diagram should actually have been 30.95 degrees. He just mis placed the angle in the wrong position.

For diagram 3 the answers would then be:

Fef = 225.9 #
Dx = 193.7 #
Dy = 466.2 #

Then the second problem was on the distances between EC and AH. In jefs textbook the distance between B and C is also 0.983 and not 0.833. The vertical distance between CD is 4.017 not 4.517. I believe Jeff just made a calculation mistake here. This gives you an angle of 58.1 degrees using arctan(4.017/2.5) in trangle CD (below member BCD), which would correspond to the angle in traingle BC on member BCD. You can then use this to find the horizontal distance AH which would then be 0.6118.

Using this information on part 1 my answers are then as follows:

Fab = 791.7 # (using moments).
Cx = -193.7 # (assumed wrong direction) or 193.7 # if assumed correct direction.
Cy = 1257.9 #

Maybe, I'm wrong, but I'm quite sure this is correct.

[nicolef]

Thank you so much for these videos, they are incredibly helpful and 100% the reason I'm doing well in statics. I have a question about how you solved for the Moment about C in FBD #1. I got the same answer when I did 1262.5 - 376.8(cos(59.06))2. But don't you have to multiply that by 2 because AB is 0.5 ft away?

[iNasserQ]

Thank You Professor! but I think the angle for F EF should be tan-1(1.5/2.5)= 30.96 NOT tan-1( 4.17/2.5)=59.06

for EF, the height is already given, which is 1.5. but you did the math to find the angle for BCD Instead.

[georgesadler]

DR. Hanson, thank you for a solid introduction to Frames with 2 Force Members. This example was long and messy.

[niconoire]

I'm glad this helped everyone else, but I think this is way too messy of an example for introducing these kinds of frame problems, especially when so many basic elements like lengths aren't given and everything becomes convoluted with trying to figure those out.

[tahiyanaoshin]

I officially hate frames but loved how Mr. Hanson taught it. Imma review it again since I didn't get it the first time

[ryanisaacson]

you should do a free body diagram drill