# Will there be a rotation around z axis?

• peter010
In summary, the two structures are beams and the criterion to decide whether or not something will rotate around the z-axis is if the perpendicular distance from the line of action is zero. Case 2 is confusing because there is a moment should be generated around z axis, but in the same time, the line of the acting force is perpendicular on the pivot.
peter010
Hello people,

I know it seems like a silly question. In case 1, its clear that no rotation will occur around z axis. Anyhow, case number 2 is confusing me; I can't decide clearly if a rotation will occur since a moment should be generated around z axis, but in the same time, the line of the acting force is perpendicular on the pivot !

what do you think please, will it rotate in case 2 ?

Last edited:
Hello Peter, welcome to PF !

So what are these ? flexible water hoses or stiff metal rods ?
A bit of description would really help clear this up !
What is the criterion to decide whether or not somethign will rotate arountd the z-axis ?

Hello,
Cheers :)

--------------
any of the two structures consists of beams.

The structure looks like the English letter "L", where in the second case, the beam in y-axis has a bucking,

in the second case, rotation means that the beam in Y axis, which is in XY plan, will rotate to the x axis.

:)

So what is the full problem statement ?
Why are those pivot points marked ?
Is there any support point somewhere ?
The F indicate loads along the y-axis ?
What is the criterion to decide whether or not something will rotate around the z-axis ?

ok,

I will upload another drawing for case 2> to be clearer :)

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no spports ? not even or the pivot points ?

And in case 1 everything is in the yz plane ?
And in case 2 everything is in the yz plane ?

the full problem statement ?

Hello,

Kindly, find this sketch.

the statement is about to answer whether the curved beam will rotate around z axis or not, at the current position, and from the steady state status, due to the applied load>

#### Attachments

• kk.jpg
30.5 KB · Views: 445
I would call this case 3, to me it looks different from the others

I take it the left-handed coordinate system is accidental -- the axis that's pointing to the right is the z axis ( -- although 'z' ?)

And I assume the 'triangle' beam - beam - curved beam can only rotate around this z-axis, and that the arc with two arrows is in the xy plane.

The perpendicular distance from the line of action is zero: the line of action goes through the candidate rotation axis.
So the torque is zero and no rotation will occur.

But it's an unstable equilbrium ...

Hi,

yes, its corresponding assumptions.

The thing which is confusing me, that this load will be analysed like in the photo, and thus a torque should be generated..

So, is there any physical way that can help to overcome this anomaly position ?

#### Attachments

• kkk.jpg
28.5 KB · Views: 433
Last edited:
by whim ?

If ##\vec F## is in the yz-plane, there can't be a net component pointing outside that plane. Your sketch suggests ##F_z## in the yz-plane and ##F_1## along the curvature or something ?

sorry I am not good in drawing :)

Is there is any way to to overcome this anomaly situation, so we can make the curved beam rotates. I said that in the meaning of modifying the curved beam design somehow in order to divert the direction of the applied force and then to create a torque that able to create rotation ?

Last edited:
• So far we've ignored the weight of the curved beam. That alone will make it rotate anti-clockwise.
• Even if the curved beam has weight 0, it still is an unstable equilibrium, so in reality it will rotate, either clockwise or anti-clockwise.

So, this may happen while the exerted force is existing in this position. right ? :)

## 1. What is rotation around the z axis?

Rotation around the z axis refers to the movement of an object around an imaginary line that runs vertically through the center of the object, perpendicular to its base.

## 2. How is rotation around the z axis different from other types of rotation?

Rotation around the z axis is different from other types of rotation because it only occurs in a two-dimensional plane, as opposed to rotation around the x or y axis which can occur in three-dimensional space.

## 3. What causes rotation around the z axis?

Rotation around the z axis is caused by a torque or force acting on an object, causing it to pivot around the imaginary line of the z axis.

## 4. Can rotation around the z axis occur in nature?

Yes, rotation around the z axis can occur in nature. For example, the Earth rotates around its z axis, causing day and night cycles, and many celestial bodies also rotate around their z axis.

## 5. How is rotation around the z axis used in science and technology?

Rotation around the z axis is used in a variety of fields such as physics, engineering, and computer graphics. It is often utilized to model and simulate the movement of objects in various systems and can also be used in robotics and space exploration.

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