Homework Help: Newton's Second Law & Moment of Inertia Derivation?

1. Mar 29, 2009

danyalasdf

1. The problem statement, all variables and given/known data
We did something very similar to this in lab

http://webenhanced.lbcc.edu/physte/phys2ate/2A LAB HANDOUTS/Moment of Inertia.pdf

Use Newton's Second to derive the expression for the experimentally determined moment of inertia

2. Relevant equations
Newton's Second Law is F=m*a

s=(1/2)*a*t^2

Experimentally Moment of Inertia

I=r^2(m((gt^2/2s)-t) - mf)

Trying to get to this ^

mf= mass effective not much meaning just mass in kg
If it confusing the gt^2 is divided by 2s then it is subtracted by t and multiplied by r^2 and then minus mf

Torque= F*r= m*r*a

T= (mf + m)(g - a) = tension

3. The attempt at a solution

T= (mf + m)(g - (2*s/t^2))

T= (mf + m)((1/2)(a*t^2) - a)

T= (mf + m)(a((1/2)*t^2 - 1)

I am stuck write here

Last edited by a moderator: Apr 24, 2017
2. Mar 29, 2009

Pythagorean

Is calculus is a prerequisite for this course?

3. Mar 29, 2009

danyalasdf

yes it is Physics Calculus Based 2211K

4. Mar 29, 2009

Pythagorean

Calc may not be necessary.

So what's the physical system you're doing in this problem? Is it the same exact system as in the lab?

5. Mar 29, 2009

danyalasdf

yes it is the exact same system