1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

  1. Mar 29, 2009 #1
    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


    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. jcsd
  3. Mar 29, 2009 #2


    User Avatar
    Gold Member

    Is calculus is a prerequisite for this course?
  4. Mar 29, 2009 #3
    yes it is Physics Calculus Based 2211K
  5. Mar 29, 2009 #4


    User Avatar
    Gold Member

    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?
  6. Mar 29, 2009 #5
    yes it is the exact same system
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook