Two force members explained (statics)

This engineering statics tutorial explains what two force members are and how they can be used to solve frames, machines, and truss problems. Basically, if a member that’s in static equilibrium only has two forces acting on it, the lines of actions of those forces must be the same, and they must have equal and opposite magnitudes. Anything else would result in an imbalanced force, and the member would begin to accelerate in some direction.

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Thanks for watching, I hope it helps!

[lamborghinicentenario]

3 years into engineering, and this is the first time I get a good explanation for 2-force members. Thanks! It was about time

[noahdangerio]

usually i am slow at understanding things, for this one I knew its definition, but was not sure why it was important. This makes things so much clearer, thank you so much!

[bhakemono]

Hey man, amazing tutorial. Just wanted to ask what program you are doing this on? Much appreciated keep it up champ.

[aryan-singh]

Thanks Sir, you explained the cases very clearly.

[hakankosebas]

What about in 3d, are them pinned or have a ball joint? Is it matter type of connection of two force member?

[furqonmuhammad]

exam tomorrow and yer video is truly useful thanks sir

[johnpatrickaguilar]

Hi there, isn't it supposed to be artan because sin is opposite over hypotenuse?

[DarkGT]

Hello sir, i find out your tutorials about C++ and Linear Algebra for very helpful, thank you !

[ravigautam]

Thank you for the tutorial. As I can see L-shaped rod is acting as two force member. But is it necessary that force acting on the free end should be along of line joining rod's end points in order to have L-shaped rod as two force member. How do find equilibrium force is in horizontal direction (it may lie in the plane of the rod).

[ravigautam]

Dear Engineers4free,
Thank you for reply. I am new to this subject. thank you for the explanation. I still have one question regrading your statement

" identifying that you have a two force member, and then realizing that the reaction must be equal and opposite to the applied force. "
Suppose I have frame with one non-straight member. Then its seems that shape of the curved member has no bearing on the equilibrium of the frame (curved member can be parabolic arc, circular arc, L-shaped rod of different sized arms). It actually seems to be same as that of a straight element! Also axial stress (or normal stress) in the curved element will be same as that of straight element. Please correct me I may be most probably wrong some where!

[shahzad]

quick question what about the mass, doesn't that exert a force

[asad]

For the second case(around 1:35), I still am not getting why that member would not be in static equilibrium if the forces cancel out. Also, how were you able to conclude that the angle just below the 10 kN force is 36.869 degrees?

[dhruvbhattofficial]

very nice video. u explained very well

[j.s.s]

thank you for the great explanation, I just wonder why do we represent the 2 force member in a frame with one force while if we to analyze the FBD of the 2force member alone we have opposite and equal forces, so in frame we shouldn’t show any force represents it ?

[wiktorkawala]

Thought this looked complicated but then realized its just Components of a force problems from M1 OCR A-level. Nice explanation though :)

[xuewenyu]

can i have your email so i can send my question to you