Why are there no signs indicating prevention of rotation in this diagram?

[werson tan]

Homework Statement

in this diagram , we know that the whole thing wouldn't rotate about y and z axis , right ? why the sign of prevention of rotation are not shown there ?
i added green sign = prevent rotation in the z axis , red = prevent rotation in the y axis

Homework Equations

The Attempt at a Solution

 

[haruspex]

Not sure what you mean by "sign of prevention of rotation". You seem to have added torques, maybe opposing rotation at B and C. Is that what you mean, that you think there should be torques there for equilibrium?

 

[werson tan]

Not sure what you mean by "sign of prevention of rotation". You seem to have added torques, maybe opposing rotation at B and C. Is that what you mean, that you think there should be torques there for equilibrium?

I'm wondering why there are no moment restriction about y and z -axis ...
from the first sight , we know that the whole structure wouldn't turn in any direction , right ?

 

[haruspex]

I'm wondering why there are no moment restriction about y and z -axis ...
from the first sight , we know that the whole structure wouldn't turn in any direction , right ?

Yes, but that can be explained entirely in terms of the linear forces shown in the second diagram.

 

[werson tan]

Can yo

Yes, but that can be explained entirely in terms of the linear forces shown in the second diagram.

Can you explain figure 2??

 

[haruspex]

Can yo

Can you explain figure 2??

What is it that puzzles you about it? It shows the linear forces at each of the three bearings, resolved into the coordinate axes.

 

[werson tan]

What is it that puzzles you about it? It shows the linear forces at each of the three bearings, resolved into the coordinate axes.

the whole structure can't rotate in x , y , and z direction right ? why the restriction of moment about y, and z axis are not shown ? only x direction(45Nm) is shown ...this puzzled me...

 

[haruspex]

the whole structure can't rotate in x , y , and z direction right ? why the restriction of moment about y, and z axis are not shown ? only x direction(45Nm) is shown ...this puzzled me...

The curved arrow around the x-axis is not a restriction of motion, it is an applied torque. Why would you expect symbols indicating a restriction of motion? I've never seen such.
Edit: do you mean reaction forces and torques?

 

[werson tan]

The curved arrow around the x-axis is not a restriction of motion, it is an applied torque. Why would you expect symbols indicating a restriction of motion? I've never seen such.
Edit: do you mean reaction forces and torques?

since the structure can't turn about x , y, and z axis ... so , there should be signs to indicate the moment restrictions about x , y and z axis , right ... just like this case...

 

[haruspex]

since the structure can't turn about x , y, and z axis ... so , there should be signs to indicate the moment restrictions about x , y and z axis , right ... just like this case...

Those are not moment restrictions. The 200Nm is an applied torque. The M_Ax and M_Az are unknown moments to be determined.
I have never seen a diagram in which 'moment restrictions' are indicated, and I'm not sure what the term would mean. Rotation about an axis is prevented by the moments of the forces. There is no deity edicting "thou shalt not turn".

 

[werson tan]

Ol

Those are not moment restrictions. The 200Nm is an applied torque. The M_Ax and M_Az are unknown moments to be determined.
I have never seen a diagram in which 'moment restrictions' are indicated, and I'm not sure what the term would mean. Rotation about an axis is prevented by the moments of the forces. There is no deity edicting "thou shalt not turn".

Ok!