The number shows a structure with a 100N thing hanging on it. Determine the magnitude and direction of pressures exerted on ab and BC respectively.

You are watching: Find the magnitude of the force at the support point.

Homework Equations

∑Fx=0, ∑Fy=0, ∑M=0

The effort at a Solution

I believe this inquiry is unsolvable. The complimentary body diagram of the frame is as follows:
*

Your FBDs space not exactly correct. Friend aren"t given any information about member BC or how it is resolved to the wall, so assuming that there is a minute at suggest C is more than likely incorrect. Similarly, abdominal is probably a continuation of the very same line which support the 100N object, and also it would certainly not be capable of sustaining a moment at point A.I think if you analyze the forces acting at suggest B, friend will acquire a better handle ~ above this problem. When you know what is going on at B, climate you can figure out what happens at A and also C to assistance the load and keep everything in equilibrium.
Your FBDs space not precisely correct. Friend aren"t given any type of information around member BC or just how it is solved to the wall, so assuming the there is a moment at point C is most likely incorrect. Similarly, abdominal is probably a extension of the same line which supports the 100N object, and it would certainly not be capable of supporting a moment at suggest A.I think if you analysis the pressures acting at point B, girlfriend will acquire a better handle on this problem. When you know what is walking on at B, climate you can number out what happens at A and also C to assistance the load and also keep every little thing in equilibrium.
Yes, i wasn"t given any type of information around how the structure is resolved to the wall. So i assumed the was addressed support that enables reactive moment.Anyway, ns don"t understand how we have the right to analyze "the pressures acting in ~ a point". Is it true that as soon as we analyze a trouble in statics, we must very first define the system? In mine FBD, I define the system as the beam. For this reason my question is, as soon as we analyze the forces acting at a point, say suggest B, what is the system?
If suggest B is not moving, climate the sum of the forces acting at suggest be B need to be zero. This is Newton"s second Law that Motion. If you draw a cost-free Body Diagram which isolates point B, understanding the orientation the the line abdominal muscle and the strut BC should provide you the direction in which these forces act to assistance the 100 N weight.
Thanks SteamKing. It seems to me that you space saying allude B is the system. Am ns right?The FBD the you defined should look like this:
*

Yes, by utilizing the above FBD, things come to be rather easy. In truth what you described was similar to the explanation provided by the textbook. You discussed that the direction of forces acting on B deserve to be figured out by the orientation that line abdominal muscle and line BC. Why is that so?
You discussed that the direction of pressures acting ~ above B have the right to be identified by the orientation that line abdominal muscle and heat BC. Why is the so?
The line supporting the weight, which additionally runs between AB, deserve to support just a stress force. The direction the this pressure must be coincident v AB, otherwise a moment will develop, which the line cannot support.Similarly, if we assume the the strut BC is not built into the wall, no moment have the right to be emerged at suggest C. Therefore, a compressive pressure will construct in the strut, due to the suspended weight, and this compressive force must also be aligned through BC.

See more: Watch Doctor Who Season 11 Episode 2 Watch Online Free On 123Movies


If ab is a rope, well,then ns agree that just tension forces can exist hence the direction of pressure should be along AB.Since the question currently mentioned that it is a beam, I suppose the structure deserve to support shear force. Right? If so, why must the pressure be along AB?
OK, let"s i think that ab and BC room some sort of framework from which the 100 N fill is suspended. Based upon the information in the OP, let"s i think the framework remains static. We are not given any type of information around how the frame is attached at points A and C, so for simplicity, let"s also assume the structure is pinned at these 2 points.We can still compose equations of revolution equilibrium because that the frame about either suggest A or C, utilizing your an initial FBD. Us make no presumptions here initially about whether the pressures in the frame are tensile or compressive. The amount of the forces in the horizontal and also vertical directions need to still amount to zero in order for the frame to stay stationary, and since the fill is vertical, that means that FAx + FCx = 0. We can see below that the direction the the horizontal materials of the pressures in the structure members should act in the opposite directions because that the frame to continue to be stationary, so that is reasonable also to conclude the one member is in tension and also the various other is in compression.If we were to relax the frame at suggest A by remove the pin, FAx would have to be directed towards the wall in bespeak to store the framework static, therefore this additionally implies, provided the equilibrium the the horizontal forces, that FCx need to act away from the wall, in the contrary direction that FAx.We have the right to do a similar qualitative evaluation of the pressures acting in the vertical direction, FAy and also FCy, yet here we must likewise consider the moment of the 100 N pack which is developed by point B being balance out from the wall.