Solve Value of R: Moment & Equilibrium

[maitake91]

Homework Statement

Solve the value of R based on the diagram attached.

Relevant Equations

Sum of moment in equilibrium = 0

Summary:: I need some help with moment when using equations of equilibrium

Edit: Sorry I forgot to say what the question was! The question was to solve the value of R based on the diagram below alone.

I was solving the question below and I tried to resolve R into a force that is perpendicular to the beam, but I couldn't. So then I looked at the workout for the answer, and apparently you don't have to do that, since they just used R to multiply 8. I don't understand why this is the case. By intuition, I imagine if I tried to push a beam with the same force but did it diagonally instead of at a position perpendicularly towards the beam, it makes more sense to me that it would spin slower. Please can someone explain to me why I am wrong? I would really appreciate the help.

 

[BvU]

Heello @maitake91 , !

the question below

I do not see any question. Please provide a complete problem description and include all given information !

https://www.physicsforums.com/threads/homework-help-guidelines-for-students-and-helpers.686781/

 

[maitake91]

Heello @maitake91 , !

I do not see any question. Please provide a complete problem description and include all given information !

https://www.physicsforums.com/threads/homework-help-guidelines-for-students-and-helpers.686781/

I'm sorry, this is my first time using Physics Forum and I wasn't sure about the rules. Thank you for the reminder! I tried to add the question, is it better now?

 

[Lnewqban]

Welcome, maitake91

Your intuition is correct: If you "tried to push a beam with the same force but did it diagonally instead of at a position perpendicularly towards the beam", the value of the resulting moment or torque would be smaller.
For the extreme case of line of application of the force intercepting the fulcrum, the torque value would be zero.

The value of R, if perpendicularly applied to the beam, would be 8.00/8.67 times smaller than the represented R.
All torques are in reference to the fulcrum A.
The reactive force that compensates for the angular application of the 500 N applied on B is Ax.
The direction of the reactive force on B can only be perpendicular to the surface that supports the rocking fixture (note its rounded base).

 

[maitake91]

Welcome, maitake91

Your intuition is correct: If you "tried to push a beam with the same force but did it diagonally instead of at a position perpendicularly towards the beam", the value of the resulting moment or torque would be smaller.
For the extreme case of line of application of the force intercepting the fulcrum, the torque value would be zero.

The value of R, if perpendicularly applied to the beam, would be 8.00/8.67 times smaller than the represented R.
All torques are in reference to the fulcrum A.
The reactive force that compensates for the angular application of the 500 N applied on B is Ax.
The direction of the reactive force on B can only be perpendicular to the surface that supports the rocking fixture (note its rounded base).

Thank you so much for your reply, it was very helpful and I understand now!

 

[Lnewqban]

You are welcome