Rotating Disk and Hanging Mass Calcululations

[badger1999]

Homework Statement

Was not given mass of disk. For some background, this lab consisted of attaching a mass (m1) onto a disk using a string. We would roll the string upwards then release the mass and record the acceleration. Following that, we are to calculate the tension of the string, angular acceleration, net torque on the wheel, and inertia. We then graph a Torque vs. Angular acceleration and use that to get the inertia. Below is an image of the system.

My trendline equation is y=0.000047x-0.000885 How do I use the trendline equation to get inertia without using the inertia formula?

Relevant Equations

angular acceleration = accerleration/radius
Tension=mg-ma
Torque=Tension*radius
Inertia=Torque/angular acceleration

I used the above equations to solve for tension, torque, inertia, and angular acceleration.
Are the formulas I used correct for the given system?
How can I calculate Inertia from the trendline equation, I'm drawing a blank.

 

[haruspex]

My trendline equation is y=0.000047x-0.000885

Since you know the angular acceleration must be zero when the torque is zero, you can use a regression method which forces the line through the origin.

How do I use the trendline equation to get inertia without using the inertia formula?

Which inertia formula do you mean?
You clearly have to use the formula which relates moment of inertia to angular acceleration and torque. If you were told not to use "the" moment of inertia formula that probably referred to deriving it from mass and radius.

Edit: you do not state your units. That 0.000047 sounds extremely small. Can you post your table of results?