Mechanics question on vector statics

AI Thread Summary
To determine the reactions at points B and D with b = 60mm, the discussion highlights the challenge of having four unknowns (Bx, By, Dx, Dy) but only three independent equations from static equilibrium. The user initially struggles to find a fourth equation, having established equations for horizontal and vertical forces and moments about point B. A suggestion is made to consider the forces at point C and to label the components of the system for clarity. Ultimately, the user confirms they found the solution after further analysis.
ashishsinghal
Messages
462
Reaction score
0
Determine the reactions at B and D when b = 60mm ?
(Diagram is attached)

Since B and D are hinged we don't know the direction as well as magnitude of the reaction forces at B and D. Hence we have 4 unknowns (Bx, By, Dx, Dy).

But I can't find 4 independent equations. I got three by ƩFx= 0, ƩFy= 0 and moment about B = 0. Where is the 4th equation. Please help.
 

Attachments

  • Capture.PNG
    Capture.PNG
    8 KB · Views: 560
Physics news on Phys.org
hi ashishsinghal! :smile:

it's static, so what can you say about the forces at C ? :wink:
 
ashishsinghal said:
Determine the reactions at B and D when b = 60mm ?
(Diagram is attached)

Since B and D are hinged we don't know the direction as well as magnitude of the reaction forces at B and D. Hence we have 4 unknowns (Bx, By, Dx, Dy).

But I can't find 4 independent equations. I got three by ƩFx= 0, ƩFy= 0 and moment about B = 0. Where is the 4th equation. Please help.

Call the ABC piece number 1 and the CD piece number 2. You know the force at point A so you have six unknowns, the two components of force at points B, C and D. You have six equations:\sum F_{1x}=0\sum F_{1y}=0\sum F_{2x}=0\sum F_{2y}=0\sum \tau_1=0\sum \tau_2=0 where \tau is torque. (I assume "b" is not an unknown).
 
Thanks Rap I got the answer.
 
Thread 'Is 'Velocity of Transport' a Recognized Term in English Mechanics Literature?'
Here are two fragments from Banach's monograph in Mechanics I have never seen the term <<velocity of transport>> in English texts. Actually I have never seen this term being named somehow in English. This term has a name in Russian books. I looked through the original Banach's text in Polish and there is a Polish name for this term. It is a little bit surprising that the Polish name differs from the Russian one and also differs from this English translation. My question is: Is there...
Thread 'Beam on an inclined plane'
Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
Back
Top