Angular Acceleration and Radius

[Kavorka]

I am writing a lab report for an experiment where we used a rotary motion sensor with different sized disks to find angular acceleration as a string attached to a falling weight unraveled and accelerated the disk. I am having confusion with my graph results and am wondering if they are correct or something is wrong.

The angular acceleration I find is increasing as the size of the spinning disk increases. From everything I have at my disposal I believe there is an inverse relationship between angular acceleration and the radius of the disk, so as the disk gets bigger the angular acceleration should decrease. Could the string be providing a lot more torque as the disk gets larger? Would you expect the tangential acceleration of the different disks to be constant, or changing as well?

 

[paisiello2]

It would depend on the relative mass of the disk and the weight. From the results it would appear that the weight's mass is much larger than the disk's.

 

[Kavorka]

The weight on the end of the string was a paperclip /:

 

[paisiello2]

Must have been a good size paper clip. What was the mass of the paper clip compared to the mass of the disks?

 

[HalfLostAndSearching]

Thank you for sharing your lab experiment and concerns about your results. It is important to carefully analyze and interpret data in order to draw accurate conclusions.

Firstly, it is important to note that angular acceleration is the rate of change of angular velocity, and it is affected by the torque applied to the object. In your experiment, the falling weight provides the torque to the disk through the string. Therefore, it is possible that the torque increases as the disk size increases, leading to a higher angular acceleration.

However, it is also important to consider the moment of inertia of the disk, which is a measure of the object's resistance to rotational motion. A larger disk would have a larger moment of inertia, which would require more torque to produce the same angular acceleration as a smaller disk. This could explain the inverse relationship you observed between angular acceleration and disk size.

In terms of tangential acceleration, it is important to remember that tangential acceleration is related to the linear speed of the object, which is affected by the radius of the disk. As the disk size increases, the linear speed at the outer edge of the disk would also increase, resulting in a higher tangential acceleration.

To ensure the accuracy of your results, it would be helpful to review your experimental setup and procedure to ensure that all variables were controlled and measured accurately. It may also be helpful to consult with your instructor or a peer to discuss your results and any possible sources of error.

Overall, your observations suggest that there may be a relationship between angular acceleration and disk size, but further analysis and investigation is needed to fully understand the relationship and any other factors that may be influencing your results. Keep up the good work in your scientific inquiry and continue to critically analyze your findings.