I always thought the shear left of the cut is drawn acting down, and right of the cut is acting up. It's confusing to see it acting down at point G and H. I thought shear at G would be acting down, and shear at H would be acting up, since its right of cut?
Yes, I have always found this confusing as well. This is by convention. Think of it as INTERNAL forces of the beam, such that the moment is an internal moment reacting to the weight of the load.
In H I dont understand why you drew the Vh arrow downward when its negative, so it should be pointing up. And that would make it a positive in Σ(Fy)=0. What's confusing is that you previously said that if Vh is downward, it's positive but in the calculations we consider it negative... but you dont apply it in this case.
I cannot understand why for section I the moment is anticlockwise. There is 300N load acting and 100N force upwards which makes net force to downwards and so net force will turn it anticlockwise. So shouldn't the M(I) be clockwise in order to oppse this moment?
You are looking at the EXTERNAL force to the beam. This is the moment of the INTERNAL forces of the beam (pushing back against the external force). (I agree it is a bit of a brain twister).
The moments of the "slices" are internal to the beam and point in the opposite direction as the moments caused by external forces (like the 100 N force )
im confused as to why no body except you explains this concept of bending moment diagram intuitevely so that it makes sense. nevertheless thankyou so much, i thought i would never understand this.
it is listed here that total videos for beam are 27 but only 11 of them are made available in this section . from where should i get the remaining videos on beam?
+MrDoYouWannaBeOnTop Are you talking about the diagrams in this video? Mechanical Engineering: Internal Forces on Beams (11 of 27) Shears & Moments of Distributed Load***
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congrats on a million subscribers !
Thank you !
I always thought the shear left of the cut is drawn acting down, and right of the cut is acting up. It's confusing to see it acting down at point G and H. I thought shear at G would be acting down, and shear at H would be acting up, since its right of cut?
Yes, I have always found this confusing as well. This is by convention. Think of it as INTERNAL forces of the beam, such that the moment is an internal moment reacting to the weight of the load.
In H I dont understand why you drew the Vh arrow downward when its negative, so it should be pointing up. And that would make it a positive in Σ(Fy)=0. What's confusing is that you previously said that if Vh is downward, it's positive but in the calculations we consider it negative... but you dont apply it in this case.
I believe it should be pointed upward
I cannot understand why for section I the moment is anticlockwise. There is 300N load acting and 100N force upwards which makes net force to downwards and so net force will turn it anticlockwise. So shouldn't the M(I) be clockwise in order to oppse this moment?
You are looking at the EXTERNAL force to the beam. This is the moment of the INTERNAL forces of the beam (pushing back against the external force). (I agree it is a bit of a brain twister).
why at H the 100 N is (+) not( - ) like other points. did the pivot point have changed?
The moments of the "slices" are internal to the beam and point in the opposite direction as the moments caused by external forces (like the 100 N force )
im confused as to why no body except you explains this concept of bending moment diagram intuitevely so that it makes sense. nevertheless thankyou so much, i thought i would never understand this.
wooow I really appreciate.
You are welcome.
why does a beam show its failure where the bending moment is high?
That is where the internal forces are the greatest.
it is listed here that total videos for beam are 27 but only 11 of them are made available in this section .
from where should i get the remaining videos on beam?
yes, we still need to go back and complete a number of the playlists.
Thankyouuu
do you have any video about shear and moment diagram?
+MrDoYouWannaBeOnTop
Are you talking about the diagrams in this video? Mechanical Engineering: Internal Forces on Beams (11 of 27) Shears & Moments of Distributed Load***
Thank you Sir!
life saver XD
😃😃👍👍 graet
Glad you found our videos. 🙂