Measuring Angular Velocity of a Hinged Iron Bar

[Cesare]

Good morning,

I have an iron bar (35 cm long) hinged on an axis. The path of this bar is limited to 45 degrees.
I have to measure the angular velocity of the bar when it rotates 45 degrees. I need to get a graph of variation of the angular velocity along the 45 degree paths. The time taken to cover 45 degrees, is about 20ms

Can You help me?
Cesar

 

[BvU]

Ave Cesar,

I have an iron bar (35 cm long) hinged on an axis. The path of this bar is limited to 45 degrees.

This is still rather ambiguous. Can you explain a bit clearer and post a picture ?

 

[Cesare]

I have attached a photo.

 

[anorlunda]

I would put a protractor in the background, then take a video. From the video you can see change in angle frame-by-frame.

 

[Cesare]

I need angular velocity and not only angle.

 

[BvU]

And what is it that causes the anglar motion ? Where does the angular motion starr ?
Where is the 45 degrees limitation you mentioned in your post #1 ?
Is there any source of friction at all ?

 

[anorlunda]

I need angular velocity and not only angle.

If your video takes 30 frames per second, and if you measure a difference A in the angle from one frame to the next frame, then angular velocity is 30A degrees per second.

 

[Cesare]

The angular motion is caused from a click of a spring that I can not known.

 

[anorlunda]

If you want a better answer, you have to explain more about what you're doing.