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: Help needed with rearranging an equation

  1. Nov 20, 2011 #1
    Im having trouble rearranging an equation to find a value for I.

    [The given equation is mgh = 1/2*Iw^2 + 1/2*mv^2 + Tf * theta

    My attempt was a bit of a stab in the dark as i am useless with rearranging equations.

    I = mgh/w^2 + 1/2*mv^2 + Tf * theta

    Many thanks
  2. jcsd
  3. Nov 20, 2011 #2
    To make I subject of the equation is like peeling an onion.

    First step: Transfer those two terms on the RHS not involving I to the LHS.
  4. Nov 20, 2011 #3
    ok so you end up with

    mgh - 1/2*mv^2 - Tf*theta = 1/2*Iw^2

    Would the lhs be divided by 1/2 w^2?

    Last edited: Nov 20, 2011
  5. Nov 20, 2011 #4
    Yes we 'peel the next layer of the onion' by dividing BOTH sides by [itex]\frac{\omega^{2}}{2}[/itex] to isolate the I by itself on the RHS.
  6. Nov 23, 2011 #5
    Nice one cheers
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook