# Angular acceleration from angular velocity

1. Mar 17, 2016

### robothito

Hello everybody. I would really appreciate some help
1. The problem statement, all variables and given/known data
I have some problem where I have measured angular velocity data. This measurements are not equally spaced, meaning there were taken after some (variable) delay passed.

I need to find what is the angular acceleration at each point of measurement.

2. Relevant equations

ummmm I don't know... perhaps α= Δω/Δt??

3. The attempt at a solution

So I have some measures like

Code (Text):

------------------------------------------------------------
15115        2.078458
24184       3.464097                  91.67310552 ???????
31238       4.453629
37207        5.263176
42474        5.964667

My question is how to fill the Acceleration values....

I have tried accel=(speed2-speed1)/(time2-time1) (see the 91.67310552)

Is this flawed??

The graphic of the speed show a almost linear increase of speed (until it becomes constant), so by theory this should give a constant acceleration and then 0 right? But my calculations become kind of crazy after a whileand give a zigzag curve after a promising start...

so can anyone check if my ideas are ok?

thanks

2. Mar 17, 2016

### andrewkirk

That's a fine way to do it. But you seem to have done the calc wrong. I get 153, not 91.7.
You can calculate four angular acceleration values from your data, and they make a nice smooth progression, with a slight, gradual decline from the original value, which seems realistic.

3. Mar 17, 2016

### robothito

Yeah I realized my calculation mistake. Thanks.
I did the calculations for all the data and I got the following graphs

Well although the speed graphs seems quite nice, the acceleration graphs have some ups and downs. I suppose physical systems are not the same as theory so instead of the square curve I was expecting I got that. Seems close enough I guess..

Thanks again for the help. It is very appreciated. It has been years since I took physics and frankly I remember very few...

4. Mar 17, 2016

### haruspex

The zigzags suggest rounding error. Can you post the data for that part?